added upload key config

Author: janithl

android/app/build.gradle

@@ -150,6 +150,15 @@ android {
             keyAlias 'androiddebugkey'
             keyPassword 'android'
         }
+
+        release {
+            if (project.hasProperty('MYAPP_UPLOAD_STORE_FILE')) {
+                storeFile file(MYAPP_UPLOAD_STORE_FILE)
+                storePassword MYAPP_UPLOAD_STORE_PASSWORD
+                keyAlias MYAPP_UPLOAD_KEY_ALIAS
+                keyPassword MYAPP_UPLOAD_KEY_PASSWORD
+            }
+        }
     }
     buildTypes {
         debug {
@@ -158,7 +167,7 @@ android {
         release {
             // Caution! In production, you need to generate your own keystore file.
             // see https://facebook.github.io/react-native/docs/signed-apk-android.
-            signingConfig signingConfigs.debug
+            signingConfig signingConfigs.release
             minifyEnabled enableProguardInReleaseBuilds
             proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
         }

android/gradle.properties

@@ -26,3 +26,9 @@ android.enableJetifier=true
 
 # Version of flipper SDK to use with React Native
 FLIPPER_VERSION=0.33.1
+
+# Upload key
+MYAPP_UPLOAD_STORE_FILE=my-upload-key.keystore
+MYAPP_UPLOAD_KEY_ALIAS=upload-key
+MYAPP_UPLOAD_STORE_PASSWORD=
+MYAPP_UPLOAD_KEY_PASSWORD=