An example of config/projections.json to support :Rj* vim commands

projections.json

{
  "app/assets/javascripts/re-student/app.coffee": {
    "command": "jini"
  },
  "app/assets/javascripts/re-student/store.coffee": {
    "command": "jstore"
  },
  "app/assets/javascripts/re-student/models/*.coffee": {
    "command": "jmodel",
    "alternate": "spec/javascripts/models/%s_spec.js.coffee",
    "template": "App.%S = DS.Model.extend"
  },
  "app/assets/javascripts/re-student/views/*.coffee": {
    "command": "jview",
    "alternate": "spec/javascripts/views/%s_spec.js.coffee",
    "template": "App.%SView = Ember.View.extend"
  },
  "app/assets/javascripts/re-student/controllers/*.coffee": {
    "command": "jcontroller",
    "alternate": "spec/javascripts/controllers/%s_spec.js.coffee",
    "template": "App.%SController = Ember.Controller.extend"
  },
  "app/assets/javascripts/re-student/routes/*.coffee": {
    "command": "jroute",
    "alternate": "spec/javascripts/routes/%s_spec.js.coffee",
    "template": "App.%SRoute = Ember.Route.extend"
  },
  "app/assets/javascripts/re-student/templates/*.emblem": {
    "command": "jtemplate"
  },
 "spec/javascripts/**/*_spec.js.coffee": {
    "command": "jspec",
    "alternate": "app/assets/javascripts/%s.coffee"
  }
}

Enables shortcuts to edit Ember.js files in vim e.g. :Rjmodel quiz is equivalent to :e app/assets/javascripts/re-student/models/quiz.coffee