code: function get_wiring_collection(req, res, next) {
  		app.db.collection('wirings', function(error, wiring_collection) {
  			if(error) { throw error; }
  			else {
  				req.wiring_collection = wiring_collection;
  				next();
  			}
  		});
  	}
docs: store the wiring collection into req.wiring_collection