add auth-service not verified with Dockerfile

backend/service-authentication/mongodbConnect.js

@@ -0,0 +1,18 @@
+const config = require('./config');
+const MongoClient = require( 'mongodb' ).MongoClient;
+const uri = config.mongodbHost;
+let db;
+
+module.exports = {
+    connectToServer: function( callback ) {
+        MongoClient.connect( uri,  { useNewUrlParser: true,  useUnifiedTopology: true }, function( err, client ) {
+            db  = client.db(config.mongodbDatabase);
+            return callback( err );
+        });
+    },
+
+    getDB: function() {
+        return db;
+    }
+};
+