Remove unused resources on build

app/build.gradle

@@ -13,10 +13,12 @@ android {
     buildTypes {
         release {
             minifyEnabled true
+            shrinkResources true
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-project.txt'
         }
         debug {
             minifyEnabled true
+            shrinkResources true
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-project.txt'
         }
     }