Add ember-cli-rails to heroku buildpack

Gemfile

@@ -49,3 +49,5 @@ end
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
+
+gem 'rails_12factor', group: [:staging, :production]

Gemfile.lock

@@ -122,6 +122,11 @@ GEM
       nokogiri (~> 1.6.0)
     rails-html-sanitizer (1.0.3)
       loofah (~> 2.0)
+    rails_12factor (0.0.3)
+      rails_serve_static_assets
+      rails_stdout_logging
+    rails_serve_static_assets (0.0.5)
+    rails_stdout_logging (0.0.5)
     railties (5.0.0)
       actionpack (= 5.0.0)
       activesupport (= 5.0.0)
@@ -182,6 +187,7 @@ DEPENDENCIES
   pg (~> 0.18)
   puma (~> 3.0)
   rails (~> 5.0.0)
+  rails_12factor
   sass-rails (~> 5.0)
   spring
   spring-watcher-listen (~> 2.0.0)

bin/heroku_install

@@ -0,0 +1,12 @@
+#!/usr/bin/env sh
+
+set -e
+
+bower="$(pwd)/node_modules/.bin/bower"
+
+for app in "frontend"; do
+  cd $app &&
+    npm install &&
+    $bower install &&
+    cd -
+done

package.json

@@ -0,0 +1,13 @@
+{
+  "scripts": {
+    "postinstall": "./bin/heroku_install"
+  },
+  "devDependencies": {
+    "bower": "*"
+  },
+  "cacheDirectories": [
+    "frontend/node_modules",
+    "frontend/bower_components",
+    "node_modules"
+  ]
+}