include firebase as devDependency

Author: yyx990803

package.json

@@ -43,6 +43,7 @@
     "eslint-plugin-html": "^1.4.0",
     "eslint-plugin-promise": "^1.1.0",
     "eslint-plugin-standard": "^1.3.2",
+    "firebase": "^3.0.5",
     "istanbul-instrumenter-loader": "^0.2.0",
     "karma": "^0.13.22",
     "karma-coverage": "^0.5.5",