Add ArangoDB logo (graphql#159)

Author: pluma

site/users/index.html.js

@@ -236,6 +236,11 @@ var logos = [
     img: 'indonesiax.png',
     link: 'https://www.indonesiax.co.id'
   },
+  {
+    name: 'ArangoDB',
+    img: 'arangodb.png',
+    link: 'https://www.arangodb.com'
+  },
   // Adding your logo?
   // Add it to the /users/logos/ directory and then append an entry above this comment.
   //