First cut at updated gradle config for codemagic code signing

android/app/build.gradle

@@ -18,7 +18,13 @@ if (flutterVersionCode == null) {
 
 def flutterVersionName = localProperties.getProperty('flutter.versionName')
 if (flutterVersionName == null) {
-    flutterVersionName = '1.0'
+    flutterVersionName = '0.8.0'
+}
+
+def keystoreProperties = new Properties()
+def keystorePropertiesFile = rootProject.file('key.properties')
+if (keystorePropertiesFile.exists()) {
+    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
 }
 
 apply plugin: 'com.android.application'
@@ -53,11 +59,27 @@ android {
         versionName flutterVersionName
     }
 
+    signingConfigs {
+        release {
+            if (System.getenv()["CI"]) { // CI=true is exported by Codemagic
+                storeFile file(System.getenv()["CM_KEYSTORE_PATH"])
+                storePassword System.getenv()["CM_KEYSTORE_PASSWORD"]
+                keyAlias System.getenv()["CM_KEY_ALIAS"]
+                keyPassword System.getenv()["CM_KEY_PASSWORD"]
+            } else {
+                keyAlias keystoreProperties['keyAlias']
+                keyPassword keystoreProperties['keyPassword']
+                storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
+                storePassword keystoreProperties['storePassword']
+            }
+        }
+    }
+
     buildTypes {
         release {
             // TODO: Add your own signing config for the release build.
             // Signing with the debug keys for now, so `flutter run --release` works.
-            signingConfig signingConfigs.debug
+            signingConfig signingConfigs.release
         }
     }
 }