title: Proguard issue while using GSON
body: <p>I am using Gson in my application and for that, i am using some classes with name as same as the one in using Json. My application works well, But while writing proguard, application crashes, I guess some of the classes are shrinking. 
  my error is :</p>
  
  <blockquote>
    <p>java.lang.ClassCastException: com.google.gson.internal.StringMap cannot be cast to com.sample.package.GsonClass</p>
  </blockquote>