Enforce nodejs version

README.md

@@ -30,7 +30,7 @@ You will need the following:
  0. [Docker 17.06.0-ce or greater](https://docs.docker.com/engine/installation/)
  0. [Ruby 2.4.2](http://rvm.io/rvm/install)
  0. [ImageMagick](https://www.imagemagick.org/script/index.php) (`brew install imagemagick` (Mac) or `sudo apt-get install imagemagick` (Ubuntu))
- 0. [Node JS > v6](https://nodejs.org/en/download/)
+ 0. [Node JS >= v8.9.0](https://nodejs.org/en/download/)
  0. [`libpq-dev` and `postgresql`](http://stackoverflow.com/questions/6040583/cant-find-the-libpq-fe-h-header-when-trying-to-install-pg-gem/6040822#6040822) and `postgresql-contrib`
  0. `gem install bundler`
 

package.json

@@ -132,6 +132,10 @@
       "html",
       "json",
       "lcov"
-    ]
+    ],
+    "engines": {
+      "node": ">=8.9.0"
+    },
+    "engineStrict": true
   }
 }