generate the Sessions controller
create the user factory and configure spec_helper to use factorygirl syntax methods
create the user factory
write the feature spec for users sign in
create sessions resource and change root to the sign in page.
Create the lagin form
create the sessions controller create action.
add remember_token field to users table
create unit test for testing the remember_token
fix type for custom flash types
change the form due to bug
modify the unit test for the remember_token
create the remember_token
add the sign_in helper for successful sign in
create helper methods for sessions
finish the user login feature specs.
extract login feature specs in to methods in the LoginMacros module