Fixed /admin/users
ArgumentError in Admin::UsersController#index
wrong number of arguments (1 for 0)

Rails 4 has depricated "all" method, now it's default behaviour
Update users_controller.rb
Update users_controller.rb
Conference Controller tests
Bugfix for Conference Controller update
Fix Hound CI violations
Installs database cleaner
- preparation for feature tests with capybara
see:
http://devblog.avdi.org/2012/08/31/configuring-database_cleaner-with-rails-rspec-capybara-and-selenium/
Implements user model tests
Bugfix to pass user model tests
Fix Hound CI violations
Merge branch 'installs_database_cleaner' into user_model_tests
Fix Hound CI violations
Switch back to sqlite test db

http://stackoverflow.com/questions/19493153/rails-4-use-sqlite-memory-db-for-selenium-driven-tests
Bugfix to pass feature test
- check if session[:return_to] is nil
- adds unique html ids for dropdown login fields
Enables capybara-webkit
Implements login macros
Implements feature tests for conference add and update
Fix Hound CI violations
Fix Travis CI build
Deletes loading seeds for tests
- we use factory girl and database cleaner instead