Connect to a database technology on start of your application (please only select one technology, try to choose something that is a good fit for your project if possible, or something you are comfortable with using)
Create a very basic user model that will be needed for login / signup of the application
Update the Readme of the application to include some instructions on how to run the application with the db locally
Here are some resources on the technologies:
Postgres - use SQLAlchemy if you are using Flask/Python and use Sequelize if you are using Node.js/Express
MongoDB - use Mongoose for Node.js or PyMongo + some object document mapper to make things organized
Here are some resources on the technologies: