Add some logic for signing releases

build.gradle

@@ -52,15 +52,44 @@ android {
 		sourceCompatibility JavaVersion.VERSION_1_7
 		targetCompatibility JavaVersion.VERSION_1_7
 	}
+
+	//
+	// To sign release builds, create the file `gradle.properties` in
+	// $HOME/.gradle or in your project directory with this content:
+	//
+	// mStoreFile=/path/to/key.store
+	// mStorePassword=xxx
+	// mKeyAlias=alias
+	// mKeyPassword=xxx
+	//
+	if (project.hasProperty('mStoreFile') &&
+			project.hasProperty('mStorePassword') &&
+			project.hasProperty('mKeyAlias') &&
+			project.hasProperty('mKeyPassword')) {
+		signingConfigs {
+			release {
+				storeFile file(mStoreFile)
+					storePassword mStorePassword
+					keyAlias mKeyAlias
+					keyPassword mKeyPassword
+			}
+		}
+		buildTypes.release.signingConfig = signingConfigs.release
+	} else {
+		buildTypes.release.signingConfig = null
+	}
+
 	buildTypes {
 		release {
 			runProguard true
 			proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
 		}
 	}
+
 	lintOptions {
 		disable 'MissingTranslation', 'InvalidPackage'
 	}
+
 	subprojects {
 
 		afterEvaluate {