How to go from a deployed ember project to local development project?

I'm using a deployed github repo project as a starting point for my own development project. Using ember-cli and ember serve I get a server running on localhost:4200. But it says

Proxying to https://xxxxx.yyy

where xxxxx.yyy is the website of the official deployed project, and the localhost:4200 server interacts with the deployed project's databases.

How do I tell ember to start a completely new local server that creates local empty databases, instead of proxying to the deployed website?