Removes .keep file
Writes api::users#create action

[#18]
Writes the 'sign_up' route using ember form helpers
Removes more .gitkeep files
Updates controllers from @killpack's changes
Adds a link from the log_in path to the sign_up path
Add some asterisks to denote "required" fields
Renames sign_up to users.new
Adds validPassword / showPasswordError
Adds missing pieces in model/controller
Writes createUser action
Fixes failing spec
Adds loginWithCredentials
Writes a feature spec for signing in
Cleans up the spec
Merge pull request #24 from gschorkopf/gschorkopf/user_sign_up

User Sign Up