add bcrypt-ruby to Gemfile
add index page
add user creation form, add session files
add current user helper
update route to login and logout
add nav with prompt and login form when no current user
update index as dashboard
add controller to session for login/authentication
add user login and signup functionality
fix redirect in Sessions#create else branch
remove flash alert from layout
Merge pull request #1 from zacholauson/userauth

User Authentication