Example of signingConfigs within build.gradle file

build.gradle

signingConfigs {
        release {
            if (System.getenv()["CI"]) { // CI is true when running build on CI service, such as Bitrise
                storeFile file(System.getenv()["BITRISE_SOURCE_DIR"] + "/keystores/my_keystore.jks")
                storePassword System.getenv()["BITRISEIO_ANDROID_KEYSTORE_PASSWORD"]
                keyAlias System.getenv()["BITRISEIO_ANDROID_KEYSTORE_ALIAS"]
                keyPassword System.getenv()["BITRISEIO_ANDROID_KEYSTORE_PRIVATE_KEY_PASSWORD"]
            } else {
                storeFile file("release.keystore")
                storePassword "Password123"
                keyAlias "app_release"
                keyPassword "Password123"
            }
        }
    }