Rails 4 2 updates

This PR will soon have a checklist of the Rails 4.2 changes to be fixed and any issues I've encountered.

PR work in progress.

__Major Features__:
 - [ ] Stock Items Creation Job
 - [ ] Email Jobs
 - [ ] Web Console
 - [ ] Foreign Key Support

__Incompatibilities__:
 - [ ] `render` with a String Argument
 - [ ] respond_with / Class-Level respond_to
 - [ ] Default Host for rails server
 - [ ] HTML Sanitizer
 - [ ] assert_select

__Railties__:
- [ ] Removals
- [ ] Deprecations
- [ ] Notable changes

__Action Pack__:
- [ ] Removals
- [ ] Deprecations
- [ ] Notable Changes

__Action View__:
- [ ] Removals
- [ ] Deprecations
- [ ] Notable Changes

__Action Mailer__:
- [ ] Removals
- [ ] Deprecations
- [ ] Notable Changes

__Active Record__:
- [ ] Removals
- [ ] Deprecations
- [ ] Notable Changes

__Active Model__:
- [ ] Removals
- [ ] Deprecations
- [ ] Notable Changes

__Active Support__:
- [ ] Removals
- [ ] Deprecations
- [ ] Notable Changes

Useless assignment to variable - `line_items`.