Check the app
module root folder for the configuration files:
config.properties
contains general configuration datarelease.properties
should contain your signing information in the following format
STORE_PASSWORD=your_store_password
KEY_ALIAS=your_key_alias
KEY_PASSWORD=your_key_password
android.keystore
your keystore for signing
The last 2 files are required only for the release build type. You can swap any of them to manage different build types (for instance, using your CI server like TeamCity).