[#8] Use grape-swagger-ui instead swagger-ui-rails

* Install swagger-ui with bower
* Configure swagger-ui using controller and view
* Configure the current API to use grape-swagger as an path version (v1)
* Rake grape routes
* Remove swagger initializer
* Update Gemfile to use the last version of grape-swagger
* Red Carpet markdown + grape-swagger

closes #8
Surrounding space missing for operator '=>'.