Add region reference via migration and model

* Create migration to add region_id to posts
* Add belongs_to :region to post model
Change routes and change links accordingly

* Change routes to place posts under regions
* Add find_regions and correct links in controller
* Correct links in post views
* Rearrange linking and navigation

* Move post creation link to region show page
* Change root to region index page
* Move header from home page to layout and delete empty home page
Add find_region to new method in post controller
Delete dead and forgotten homes controller
Remove unnecessary instance variables

* Better follow Sandi Metz's rules
Merge pull request #14 from elijahkim/ha-add-region

Add region to posts