We'll have to create a user in the server's mongoDB.
Log into the server as an admin. Select the database that you want to use. Then create a user for that database.
use DATABASE_NAME
db.createUser({user:"USER_NAME", pwd:"PASSWORD",roles:[{role:"readWrite",db:"DATABASE_NAME"}]})
use devkittens
db.createUser({user:"devkittens", pwd:"5585B1722E9206A4704061E26A2E69F560487768C150D5501039CE7F9693A179",roles:[{role:"readWrite",db:"devkittens"}]})
In your code, you'll want to edit you mongoDB connection URI. If you don't want to create users on your local machine, put the connection string either a configuration file or enviromental variable.
mongodb://{USER_NAME}:{PASSWORD}@localhost:27017/{DATABASE_NAME}
mongodb://devkittens:5585B1722E9206A4704061E26A2E69F560487768C150D5501039CE7F9693A179@localhost:27017/devkittens