change vcr record interval
clean gems
access rack session on capybara tests
use email sequence for user factory
restrict listing creation to authorized users
show listing actions to correct user
Merge branch 'feature/authorization' into develop

* feature/authorization:
  show listing actions to correct user
  restrict listing creation to authorized users
  use email sequence for user factory
  access rack session on capybara tests
  clean gems
  change vcr record interval
add database table and assocations for favorite listings
add controller action for favorite listings
add buttons to mark a listing as favorite/unfavorite
Merge branch 'feature/favorites' into develop

* feature/favorites:
  add buttons to mark a listing as favorite/unfavorite
  add controller action for favorite listings
  add database table and assocations for favorite listings
restrict user to not favorite his own listings