Update firebase package version

Author: nicolasgarnier

database/package.json

@@ -7,7 +7,7 @@
   "license": "Apache License Version 2.0",
   "dependencies": {
     "escape-html": "^1.0.3",
-    "firebase": "^3.0.0",
+    "firebase": "^3.5.1",
     "node-schedule": "^1.1.0",
     "nodemailer": "^2.4.1",
     "promise": "^7.1.1"