making it work by solving npm issues around koa-ratelimit module.

package.json

@@ -8,6 +8,10 @@
     "email": "niftylettuce@gmail.com"
   },
   "dependencies": {
+    "babel-plugin-syntax-async-generators": "^6.8.0",
+    "babel-plugin-transform-async-to-generator": "^6.8.0",
+    "babel-regenerator-runtime": "^6.5.0",
+    "babel-runtime": "^5.3.0",
     "boom": "^3.1.3",
     "bootstrap": "^4.0.0-alpha.2",
     "chalk": "^1.1.3",
@@ -36,13 +40,14 @@
     "koa-no-trailing-slash": "^1.1.0",
     "koa-nunjucks-promise": "^1.0.3",
     "koa-passport": "^2.0.1",
-    "koa-ratelimit": "github:niftylettuce/ratelimit",
+    "koa-ratelimit": "latest",
+    "koa-ratelimit-promises": "latest",
     "koa-redis": "^2.0.1",
     "koa-response-time": "^1.0.2",
     "koa-router": "^7.0.0",
     "lodash": "^4.12.0",
     "moment": "^2.13.0",
-    "mongodb": "^2.1.18",
+    "mongodb": "^2.1.21",
     "mongoose": "^4.4.16",
     "mongoose-beautiful-unique-validation": "^3.0.0",
     "mongoose-json-select": "^0.2.1",