Added Progaurd rules

app/build.gradle

@@ -2,6 +2,15 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
 apply plugin: 'kotlin-kapt'
+apply plugin: "ru.cleverpumpkin.proguard-dictionaries-generator"
+
+proguardDictionaries {
+    dictionaryNames = [
+            "build/class-dictionary",
+            "build/package-dictionary",
+            "build/obfuscation-dictionary"
+    ]
+}
 
 android {
     compileSdkVersion 29

app/proguard-rules.pro

@@ -67,4 +67,12 @@
 -keep class code.name.monkey.retromusic.cast.CastOptionsProvider { *; }
 -keep class android.support.** { *; }
 -keep class com.google.** { *; }
--keep class java.nio.file.** { *; }
+-keep class java.nio.file.** { *; }
+
+-obfuscationdictionary build/obfuscation-dictionary.txt
+-classobfuscationdictionary build/class-dictionary.txt
+-packageobfuscationdictionary build/package-dictionary.txt
+
+# Move all classes and packages into the root package.
+-repackageclasses ''
+-flattenpackagehierarchy

build.gradle

@@ -5,11 +5,15 @@ buildscript {
     repositories {
         jcenter()
         google()
+        maven {
+            url "https://plugins.gradle.org/m2/"
+        }
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.5.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath 'com.android.tools.build:bundletool:0.9.0'
+        classpath "gradle.plugin.ru.cleverpumpkin.proguard-dictionaries-generator:plugin:1.0.7"
     }
 }