Added release signing config

.gitignore

@@ -38,6 +38,9 @@ captures/
 # Keystore files
 # Uncomment the following line if you do not want to check your keystore files in.
 #*.jks
+/*.properties
+/keystore.properties
+/app/keystore.jks
 
 # External native build folder generated in Android Studio 2.2 and later
 .externalNativeBuild
@@ -59,3 +62,4 @@ fastlane/readme.md
 /app/release/app-release.aab
 /app/release/app-release.apk
 /app/release/output-metadata.json
+/app/release/