Add locations and prices to posts

Enable users to specify a sales price for their item
Enable users to specify their location
Add locations and prices to posts

Users can now choose a location from a select list, and enter a dollar
amount for the price of the item being posted.

New post form only appears if user is signed in.
Add locations and prices to posts

- Users can now choose a location from a select list, and enter a dollar
amount for the price of the item being posted.

- New post form only appears if user is signed in.
Cleaned up some spacing
Fix spacing for in posts controller

Added a trello card for refactoring post creation to remove merge.
Refactor user id merge in posts controller
Validate on location instead of location_id

Didn't change the collection_select, because adding the"form." causes
the server to attempt a merge that then fails.
Add "form." to collection_select for locations

Had to remove :post from the variable list to make it work without merge
error.
Merge branch 'lea-add-locations-prices-to-posts'

* lea-add-locations-prices-to-posts:
  Add "form." to collection_select for locations
  Validate on location instead of location_id
  Refactor user id merge in posts controller
  Fix spacing for in posts controller
  Cleaned up some spacing
  Add locations and prices to posts
  Add locations and prices to posts
  Add locations and prices to posts
  change location.location to location.name
  add location show page