Move rspec into the test group

[sandbergja]

What maintenance needs to be done?

Move the rspec gem into the test group of the Gemfile. Adjust the Rakefile so that rake tasks (for example, the solr backup task) still run in staging and production, even if rspec is not installed.

Level of urgency

• High
• Moderate
• Low

Why is this maintenance needed?

Rspec is only used for tests, so it is not needed on the staging or prod boxes.

Acceptance criteria

• Rspec is not installed when we deploy to staging and prod
• The backup rake task can still run okay in staging and prod, even without rspec installed.