title: retrofit convertor factory can not access GsonConverterFactory
body: <p>I have included these dependencies to my project:</p>
  
  <blockquote>
    <p>compile 'com.squareup.retrofit:retrofit:2.0.0-beta2'<br>
    compile 'com.squareup.retrofit:converter-gson:2.0.0-beta1'</p>
  </blockquote>
  
  <p>I have a class where I am going to access my api's via retrofit:</p>
  
  <pre><code> public static  &lt;S&gt; S createService(Class&lt;S&gt; serviceClass, String baseUrl) {
  
  
          Retrofit builder = new Retrofit.Builder()
                  .baseUrl(baseUrl)
                  .addConverterFactory(GsonConverterFactory.create())
                  .build();    
  
              RestAdapter adapter = builder.build();*/
  
          return  builder.create(serviceClass);
      }
  </code></pre>
  
  <p>And now, it gives me this compile time error :</p>
  
  <blockquote>
    <p>Error:(24, 17) error: method addConverterFactory in class Builder
    cannot be applied to given types; required: Factory found:
    GsonConverterFactory reason: actual argument GsonConverterFactory
    cannot be converted to Factory by method invocation conversion</p>
  </blockquote>
  
  <p>How can I solve this? I followed the documentation. What is wrong? </p>