Updated capybara
Updated bootsrap gems
Modified discussions controller tests
Added admin dropdown in the nav bar
Changed 'Join' link in the nav bar to 'Sign up'
Organised the nav code
Show join button in the home page if th user is not looged in.
Added email subscription field in users
When user is editing profile, show email_subscription option when the current user is not admin or email_subscription was false
Added a hint in current_password field in users edit view
Generated user mailer
Added notification user mailer templates
Removed user mailer text template
Added a 'hi user' to the notification user mailer
Finished with notifications
Installed ckedidor_rails gem
Updated ckedidor gem
Revert "Updated ckedidor gem"

This reverts commit cbd54a8466cfd1ea2ca92106c2386eb484511911.
Revert "Installed ckedidor_rails gem"

This reverts commit b3729c90765a09fe92aae3eae4bc5d72ddf00525.
Added ckeditor source in assets