title: Can't generate signed APK in Android Studio, because proguard-rules.txt is missing
body: <p>I have a problem with generating signed APK in Android Studio. After fixing all the warnings I am stuck on this one:</p>
  
  <blockquote>
    <p>Error:Execution failed for task ':app:proguardRelease'.
    java.io.FileNotFoundException: /Users/franek/Documents/Android_Studio_Melange/app/proguard-rules.txt (No such file or directory)</p>
  </blockquote>
  
  <p>I don't want to change minifyEnabled to false, because I want to keep Proguard working. How can I fix this error?</p>
  
  <p>A fragment of build.gradle:</p>
  
  <pre><code>buildTypes {
          release {
              minifyEnabled true
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
          }
      }
  </code></pre>