The source code for both, the application and this website are available for download publicly at Github:
They are both licensed under the AGPLv3.
There is no need to create an account with GitHub to clone the source.
You are encouraged to fork and reuse the code. This way you can deploy the app on both Android and iOS devices without the use of any app or play store.
Pull requests though might not be merged in easily for liability reasons. Get it touch before you invest time into improving Encrateia’s code.