doc: update readme (#25)

README.md

@@ -1,2 +1,54 @@
 # zksync-state-reconstruct
-Tool / Library to reconstruct zkSync state from commit blocks
+> Tool / Library to reconstruct zkSync state from commit blocks
+
+## Prerequisites
+This tool is written in nightly Rust; you can install Rust by following the official instructions [here](https://www.rust-lang.org/learn/get-started), and then running the following command to switch to the nightly toolchain:
+
+```fish
+rustup toolchain install nightly
+```
+
+## Usage
+To start reconstructing the state, run the following command with a valid HTTP/HTTPS Etherum JSON-RPC endpoint:
+
+```fish
+cargo +nightly run -- reconstruct l1 --http-url <HTTP_URL>
+```
+
+To view all available options you can use the `help` command:
+
+```fish
+$ cargo +nightly run -- --help
+
+zkSync state reconstruction tool
+
+Usage: state-reconstruct <COMMAND>
+
+Commands:
+  reconstruct  Reconstruct L2 state from a source
+  query        Query the local storage, and optionally, return a JSON-payload of the data
+  help         Print this message or the help of the given subcommand(s)
+
+Options:
+  -h, --help     Print help
+  -V, --version  Print version
+```
+
+You can also view all the options for the subcommands in a similar fashion:
+
+```fish
+$ cargo +nightly run -- reconstruct --help
+
+Reconstruct L2 state from a source
+
+Usage: state-reconstruct reconstruct [OPTIONS] <COMMAND>
+
+Commands:
+  l1    Fetch data from L1
+  file  Fetch data from a file
+  help  Print this message or the help of the given subcommand(s)
+
+Options:
+  -d, --db-path <DB_PATH>  The path to the storage solution [env: ZK_SYNC_DB_PATH=]
+  -h, --help               Print help
+```