Add build type release and use of proguard

app/build.gradle

@@ -32,12 +32,12 @@ android {
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
 
-//    buildTypes {
+    buildTypes {
-//        release {
+        release {
-//            minifyEnabled true
+            minifyEnabled true
-//            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
-//        }
+        }
-//    }
+    }
 
     configurations {
         all*.exclude group: 'com.google.guava', module: 'listenablefuture'