added SendGrid config for heroku
add .env to .gitignore
added rails_12factor gem to production
added ruby version to gemfile
added ruby version to gemfile
Adding oauth github
added facebook login in devise
Added login with gmail and github
added fb, gmail, github icons to login
Added Sign in & Sign out buttons
added AJAX to question rating
added Markdown format processor, still have some issues with AJAX - can't show error messages
Repaired some little issues