Add migration files, models and test for models
Add routing paths skeleton and files
implement session controller and its tests
modify route path profiles#show to profiles#details
modify profiles to users
merge development branch
modify request error status code to be 400
modify all error messages to be returned as an array to allow consistency
modify skip authentication_user before action to only occur for create action
delegate log in and log out functionality into application controller
implement part of user controller
fix bugs: gender and user association; as_json representation of user
implement tests for user#create controller with valid user
fix comment for HTTP status to be returned in invalid user session creation
Merge branch 'development' into feature/profile-controller
add tests to users controller to test POST #create with invalid user
override rake's populate command to fill database with testing data