Install fxos addon

package.json

@@ -27,6 +27,7 @@
     "ember-cli-content-security-policy": "0.4.0",
     "ember-cli-dependency-checker": "^1.0.0",
     "ember-cli-font-awesome": "0.1.0",
+    "ember-cli-fxos": "0.1.2",
     "ember-cli-htmlbars": "0.7.9",
     "ember-cli-htmlbars-inline-precompile": "^0.1.1",
     "ember-cli-ic-ajax": "0.2.1",

public/manifest.webapp

@@ -9,8 +9,7 @@
     "90": "/assets/images/icons/icon-90.png",
     "120": "/assets/images/icons/icon-120.png",
     "128": "/assets/images/icons/icon-128.png",
-    "256": "/assets/images/icons/icon-256.png",
-    "512": "/assets/images/icons/icon-512.png"
+    "256": "/assets/images/icons/icon-256.png"
   },
   "developer": {
     "name": "@@developerName",