diff --git a/group-membership/.eslintrc.json b/group-membership/.eslintrc.json
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+{
+  "parserOptions": {
+    "ecmaVersion": 6
+  },
+  "extends": "../configs/appsscript.eslintrc.json"
+}
diff --git a/group-membership/README.md b/group-membership/README.md
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+---
+title: Scale access for external vendors and partners
+description: Share documents, events, and communications with users outside
+your domain
+labels:  Sheets, Groups, Apps Script
+material_icon: group_work
+create_time: 2019-08-30
+update_time: 2020-3-27
+---
+Contributed by Tech and Eco, follow me on
+[Twitter](https://twitter.com/TechandEco)!
+
+Use a Google Group to work cross-functionally with vendors, partners,
+customers, and volunteers outside of your domain, and scale access
+to work assignments and leverage security controls. You can add an external
+user's Google email (this can be their own G Suite account, a G Suite user
+account you created for them within your domain, or a free Gmail account) to
+your G Suite Google group (not available for consumer Google Groups) via a
+Google Sheet to manage users in bulk and keep track of the onboarding history.
+
+Top 6 benefits of this solution:
+
+ 1. Adds a new external user to a G Suite Google Group you create
+   (example: externalteam@mydomain.com) once, and it allows users to open all
+   resources that are shared with that group moving forward (calendar, files,
+   training site, dashboards (built on DataStudio), etc.
+
+ 1. When adding one or more users to your Google Group, users can receive a
+    welcome email with the links they can access.
+    [Creating a Google Site](https://sites.google.com/new) is optional but
+    recommended to centralize information in a beautiful website interface.
+
+ 1. The
+    [template of the welcome email](https://docs.google.com/document/d/1GZDh_u9B2ARpYs3Iks8ZouQ_Xlixq076kAst710Z4cg/edit?usp=sharing)
+    is composed in a Google Doc, and the script renders it as HTML. You can use
+    seperate Google Docs for different recipients to customize messaging.
+
+ 1. Capture the email addresses of users in your Sheet, and add them in bulk to
+    the desired Google Groups at a later time by changing the column "Allowed"
+    to "yes" for each row of users.
+
+ 1. You or members of your team, can add users to different Google Groups as
+    long as the person who made a copy of this sheet has
+    _manager_ or _owner_ rights in each of those Google Groups.
+
+ 1. Removing a user from a Group (via the Google Group's interface) will revoke
+    their access to all resources. You can also limit documents to be available
+    to that group for a
+    [specific period of time](https://support.google.com/docs/answer/2494893?co=GENIE.Platform%3DDesktop&hl=en).
+
+![Users are added to a Google Group via a Google Sheet](https://cdn.jsdelivr.net/gh/gsuitedevs/solutions@master/group-membership/demo.gif)
+
+## Technology highlights
+
+- Install a trigger with a click so the script is setup to run everytime the
+Sheet is edited. To learn more visit the
+ [Apps Script trigger guide](https://developers.google.com/apps-script/guides/triggers/installable))
+- Add members to a _Google Group for Business_ using the
+ [Admin Directory API](https://developers.google.com/apps-script/advanced/admin-sdk-directory)
+
+## Try it
+
+1. Copy the [External Sustainability Group List](https://docs.google.com/spreadsheets/d/1toqdDkWSAOL7aIElil59RHJH0b1Efebg7GBlgjn3B2Y/copy) from your _G Suite_ account.
+
+1. Enter for testing purposes a _Gmail address you own_ and a Google Group you
+   have _rights to manage_ its membership. You can learn about
+   [group permissions here](https://support.google.com/groups/answer/2464975?hl=en)
+
+   > _Note_: The membership status will be populated by the words
+   > **Newly added** if the user was added to the group, or **Already added**
+   > if it recognizes the user is already a member of that group.
+
+1. Enter “Yes” in the “Allowed” column.
+
+1. Next, click the custom menu called **Install Trigger** > **onEdit**, this
+   will install a trigger that will run everytime a value is changed in the
+   sheet.
+
+   ![Install trigger screenshot](https://cdn.jsdelivr.net/gh/gsuitedevs/solutions@master/group-membership/install_trigger.png)
+
+1. When prompted, click the **Review permissions** and click **Allow** so the
+   script can email on your behalf.
+
+   > _Note_: If you get a warning that **This app isn't verified** continue
+   > with the verification process by clicking **Advanced** and then scroll
+   > down and click the grey text at the bottom that begins with **Go to...**
+
+1. Your status field will change.
+
+![Status column is changed](https://cdn.jsdelivr.net/gh/gsuitedevs/solutions@master/group-membership/final_group_add.gif)
+
+1. Check your inbox to see the email, and then your Google Group’s interface
+   to see the new member added.
+
+## _[optional]_ Customize your messaging
+
+- If you wish to change the subject lines of your emails, replace
+ the text in the “Email subject” column.
+
+- If you wish to change the
+  [email template](https://docs.google.com/document/d/1GZDh_u9B2ARpYs3Iks8ZouQ_Xlixq076kAst710Z4cg/edit#heading=h.uwtpzkmp9874)
+  that is sent out, replace the URL in the “Email template” column with your
+  preferred Google Doc. If you wish to include any of the column values in the
+  template, enter them as such in the template {{Column_name}} like
+  this: _Welcome, we have added your {{Email}} to this {{Google_Group}} in
+  order give you access to the following resources..._
+  > _Note_: If you encounter any issues with the welcome email, change the
+  > permission levels of the Google Doc templates to more open settings.
+
+## Next steps
+
+To get started with Google Apps Script, try out [the codelab][codelab]
+which guides you through the creation of your first script.
+
+You can also view the [full source code][github] of this solution on GitHub to
+learn more about how it was built.
+
+[codelab]: https://codelabs.developers.google.com/codelabs/apps-script-intro
+[github]: https://github.com/gsuitedevs/solutions/blob/master/group-membership
diff --git a/group-membership/data/sheet-data.xlsx b/group-membership/data/sheet-data.xlsx
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diff --git a/group-membership/final_group_add.gif b/group-membership/final_group_add.gif
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diff --git a/group-membership/install_trigger.png b/group-membership/install_trigger.png
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diff --git a/group-membership/src/Code.js b/group-membership/src/Code.js
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+++ b/group-membership/src/Code.js
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+const EMAIL = 'Email';
+const GOOGLE_GROUP = 'Google Group';
+const ALLOWED = 'Allowed';
+const EMAIL_TEMPLATE_DOC_URL = 'Email template doc URL';
+const EMAIL_SUBJECT = 'Email subject';
+const EMAIL_STATE = 'Email state';
+
+/**
+ * Email state base class.
+ */
+class EmailState {
+  /**
+   * Converts state to string.
+   * @return {string}
+   */
+  toString() {
+    return '';
+  }
+}
+
+/**
+ * 'Email sent' state.
+ */
+class StateSent extends EmailState {
+  /**
+   * Class constructor.
+   * @param {Date} date - date when the email was sent.
+   */
+  constructor(date) {
+    super();
+    this.date = date;
+  }
+  /**
+   * Converts state to string.
+   * @return {string}
+   */
+  toString() {
+    return `Sent: ${this.date}`;
+  }
+}
+
+/**
+ * 'Already in group' state.
+ */
+class StateAlreadyInGroup extends EmailState {
+  /**
+   * Converts state to string.
+   * @return {string}
+   */
+  toString() {
+    return 'Already in group';
+  }
+}
+
+/**
+ * 'Not sent' state.
+ */
+class StateNotSent extends EmailState {
+  /**
+   * Converts state to string.
+   * @return {string}
+   */
+  toString() {
+    return 'Not sent';
+  }
+}
+
+/**
+ * 'Requiered field missing' state.
+ */
+class StateRequiredFieldMissing extends EmailState {
+  /**
+   * Class constructor.
+   * @param {string} user - email of user to add to the group.
+   * @param {string} group - address of Google Group to add user to.
+   * @param {string} template - Google Doc URL that serves as template
+   *        of the welcome email sent to a user added to the group.
+   * @param {string} subject - subject of welcome email sent to user added
+   */
+  constructor(user, group, template, subject) {
+    super();
+    this.user = user;
+    this.group = group;
+    this.template = template;
+    this.subject = subject;
+  }
+  /**
+   * Converts state to string.
+   * @return {string}
+   */
+  toString() {
+    return `Required field missing: ${
+        !this.user ? EMAIL :
+        !this.group ? GOOGLE_GROUP :
+        !this.template ? EMAIL_TEMPLATE_DOC_URL :
+        EMAIL_SUBJECT}`;
+  }
+}
+
+/**
+ * 'Allowed field not specified' state.
+ */
+class StateAllowedFieldNotSpecified extends EmailState {}
+
+/**
+ * 'Error' state.
+ */
+class StateError extends EmailState {
+  /**
+   * Class constructor.
+   * @param {Exception} error - error message.
+   */
+  constructor(error) {
+    super();
+    this.error = error;
+  }
+  /**
+   * Converts state to string.
+   * @return {string}
+   */
+  toString() {
+    return `${this.error}`;
+  }
+}
+
+/**
+ * Installs a trigger in the Spreadsheet to run upon the Sheet being opened.
+ * To learn more about triggers read:
+ * https://developers.google.com/apps-script/guides/triggers
+ */
+function onOpen() {
+  SpreadsheetApp.getUi()
+      .createMenu('Install trigger')
+      .addItem('onEdit', 'installOnEditTrigger')
+      .addToUi();
+}
+
+/**
+ * Installs a trigger in the Spreadsheet that is scheduled
+ * to run upon when values in the Sheet are edited.
+ * To learn more about triggers read:
+ * https://developers.google.com/apps-script/guides/triggers/installable
+ */
+function installOnEditTrigger() {
+  ScriptApp.newTrigger('onEditInstallableTrigger')
+      .forSpreadsheet(SpreadsheetApp.getActive())
+      .onEdit()
+      .create();
+}
+
+/**
+ * Trigger that runs on edit after being installed via the interface.
+ *
+ * @param {Object} e - onEdit trigger event.
+ */
+function onEditInstallableTrigger(e) {
+  // Don't do anything if the header row (first row) was updated.
+  if (e.range.getRow() == 1) {
+    return;
+  }
+
+  // Get the headers, row range and values from the active sheet.
+  const sheet = SpreadsheetApp.getActiveSheet();
+  const headers = sheet.getDataRange().offset(0, 0, 1).getValues()[0];
+  const range = sheet.getRange(e.range.getRow(), 1, 1, headers.length);
+  const row = range.getValues()[0];
+
+  // Convert the row Array into an entries Object using the headers for the
+  // field names.
+  const entries = headers.reduce((result, columnName, i) => {
+    result[columnName] = row[i];
+    return result;
+  }, {});
+
+  // Update the entries Object with the email state returned by addToGroup().
+  try {
+    entries[EMAIL_STATE] = addToGroup(
+        entries[EMAIL],
+        entries[GOOGLE_GROUP],
+        entries[ALLOWED],
+        entries[EMAIL_TEMPLATE_DOC_URL],
+        entries[EMAIL_SUBJECT]
+    ).toString();
+  } catch (e) {
+    // If there's an error, report that as the email state.
+    entries[EMAIL_STATE] = new StateError(e).toString();
+  }
+
+  // Convert the updated entries Object into a row Array.
+  const rowToWrite = headers.map((columnName) => entries[columnName]);
+
+  // setValues() receives a 2D array, so we create an array with the row
+  // contents.
+  console.log(JSON.stringify(rowToWrite));
+  range.setValues([rowToWrite]);
+}
+
+
+/**
+ * Trigger that runs on edit after being installed via the interface.
+ *
+ * @param {string} userEmail - email of user to add to the group.
+ * @param {string} groupEmail - address of Google Group to add user to.
+ * @param {string} allowed - 'yes' flag to add user to group.
+ * @param {string} emailTemplateDocUrl - Google Doc URL that serves as template
+ *        of the welcome email sent to a user added to the group.
+ * @param {string} emailSubject - subject of welcome email sent to user added
+ *        to group.
+ * @return {EmailState} - state if email was sent to a user added in the sheet.
+ */
+function addToGroup(userEmail, groupEmail, allowed, emailTemplateDocUrl, emailSubject) {
+  if (!allowed) {
+    return new StateAllowedFieldNotSpecified();
+  }
+  if (!userEmail || !groupEmail || !emailTemplateDocUrl || !emailSubject) {
+    return new StateRequiredFieldMissing(
+        userEmail, groupEmail, emailTemplateDocUrl, emailSubject);
+  }
+  if (allowed.toLowerCase() != 'yes') {
+    return new StateNotSent();
+  }
+
+  // If the group does not contain the user's email, add it and send an email.
+  const group = GroupsApp.getGroupByEmail(groupEmail);
+  if (!group.hasUser(userEmail)) {
+    // User is not part of the group, add user to the group.
+    const member = {email: userEmail, role: 'MEMBER'};
+    AdminDirectory.Members.insert(member, groupEmail);
+
+    // Send a confirmation email that the member was now added.
+    const docId = DocumentApp.openByUrl(emailTemplateDocUrl).getId();
+
+    // Replace the template variables like {{VARIABLE}} with real values.
+    const emailBody = docToHtml(docId)
+        .replace('{{EMAIL}}', userEmail)
+        .replace('{{GOOGLE_GROUP}}', groupEmail);
+
+    MailApp.sendEmail({
+      to: userEmail,
+      subject: emailSubject,
+      htmlBody: emailBody,
+    });
+
+    return new StateSent(new Date());
+  }
+  return new StateAlreadyInGroup();
+}
+
+/**
+ * Fetches a Google Doc as an HTML string.
+ *
+ * @param {string} docId - The ID of a Google Doc to fetch content from.
+ * @return {string} The Google Doc rendered as an HTML string.
+ */
+function docToHtml(docId) {
+  const url = 'https://docs.google.com/feeds/download/documents/export/Export?id=' +
+            docId + '&exportFormat=html';
+  const param = {
+    method: 'get',
+    headers: {'Authorization': 'Bearer ' + ScriptApp.getOAuthToken()},
+    muteHttpExceptions: true,
+  };
+  return UrlFetchApp.fetch(url, param).getContentText();
+}
diff --git a/group-membership/src/appsscript.json b/group-membership/src/appsscript.json
new file mode 100644
index 00000000..f526cf6c
--- /dev/null
+++ b/group-membership/src/appsscript.json
@@ -0,0 +1,22 @@
+{
+  "timeZone": "America/Los_Angeles",
+  "dependencies": {
+    "enabledAdvancedServices": [{
+      "userSymbol": "AdminDirectory",
+      "serviceId": "admin",
+      "version": "directory_v1"
+    }]
+  },
+  "exceptionLogging": "STACKDRIVER",
+  "runtimeVersion": "V8",
+  "oauthScopes": [
+    "https://www.googleapis.com/auth/admin.directory.group.member",
+    "https://www.googleapis.com/auth/documents",
+    "https://www.googleapis.com/auth/drive.readonly",
+    "https://www.googleapis.com/auth/groups",
+    "https://www.googleapis.com/auth/script.external_request",
+    "https://www.googleapis.com/auth/script.scriptapp",
+    "https://www.googleapis.com/auth/script.send_mail",
+    "https://www.googleapis.com/auth/spreadsheets.currentonly"
+  ]
+}