Creating a key.properties file

To build a properly signed release you need your keystore file and a key.properties file.

Your key.properties file will look like this:

storepassword=$YOUR_STOREPASSWORD
keypassword=$YOUR_KEYPASSWORD
keyalias=$YOUR_KEYALIAS
storefile=$PATH_TO_STOREFILE

You'll need to fill in the spots with your passwords, alias, and the path to your .jks file, and place this key.properties file in the android/ folder in the root of the repo. Now you can build a signed apk with flutter!