First steps to make it configurable for other projects

* We should only copy `database.yml` if it does not exist
* Put db/schema.rb under version control
* We need to `rake db:migrate` before we can `db:test:load`
* Extracted lead color variable in SCSS
* Introduce a simple configuration file
* Remove nested test method definition to prevent the following warning:
```
CommitsControllerTest#test_in_edgetest/unit warning: method CommitsControllerTest#test_index_for_contributors is redefined
```