EmberCLI Rails Addon

This is an integration piece between the ember-cli-rails gem and the EmberCLI applications the Rails applications serve.

This addon is responsible for:

• exposing an initializer for sending Rails' CSRF tokens
• setting expected build variables without the user having to manipulate their EmberCLI app's ember-cli-build.js
• creating lockfiles that ember-cli-rails tracks to ensure that requests halt until EmberCLI has had a chance to fully build
• writing build errors to a file so that ember-cli-rails can display them as Rails errors.