Creates bar model, controller, and views

* Allows user to create a bar
* Adds validations for bar model fields
* Creates index, new, show views and bar partial
* Creates error messages partial
* Scopes bar name field uniqueness to address, city, and state
* Creates _bars partial in addition to _bar partial
* Adds multiple fields to index scope to allow for bars with same name
Merge pull request #3 from mtdowd/bar-model

Creates bar model, controller, and views (new, create, show, index)