Adding setup to README; symlink pre-commit hook

Author: Konstantin Gredeskoul

README.md

@@ -13,6 +13,16 @@
 
 <!-- /TOC -->
 
+# Setup
+
+To get the initial stuff setup required by this repo, please run the script:
+
+```bash
+bin/setup
+```
+
+Whenever you'll commit something, a pre-commit hook will run as well.
+
 # Rules Ruby
 
 [![Build Status](https://travis-ci.org/bazelruby/rules_ruby.svg?branch=master)](https://travis-ci.org/bazelruby/rules_ruby)

bin/setup

@@ -23,5 +23,5 @@ inherit_gem:
   run "git add .rubocop.yml"
 }
 
-
+[[ -L .git/hooks/pre-commit ]] || run "ln -nfs bin/pre-commit .git/hooks/pre-commit"