title: strongloop loopback android sdk extending installation class
body: <p>I am using the loopback android sdk example and  trying to extend Installation Class in android SDK to add more attribute to the installation . But when I add add a new attribute it gives me the following error.</p>
  
  <pre><code>11-16 20:51:33.207    4339-4339/com.google.android.gcm.demo.app E/GCM Demo﹕ Cannot save Installation
  org.apache.http.client.HttpResponseException: Unprocessable Entity
          at com.loopj.android.http.AsyncHttpResponseHandler.sendResponseMessage(AsyncHttpResponseHandler.java:235)
          at com.loopj.android.http.AsyncHttpRequest.makeRequest(AsyncHttpRequest.java:79)
          at com.loopj.android.http.AsyncHttpRequest.makeRequestWithRetries(AsyncHttpRequest.java:95)
          at com.loopj.android.http.AsyncHttpRequest.run(AsyncHttpRequest.java:57)
          at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:422)
          at java.util.concurrent.FutureTask.run(FutureTask.java:237)
          at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
          at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
          at java.lang.Thread.run(Thread.java:841)
  </code></pre>
  
  <p>The way I am doing it is,</p>
  
  <pre><code>public class CustomInstallation extends LocalInstallation {
  
  
  public static final java.lang.String DEVICE_IMEI= "imei";
  private String imeiNumber;
  
  
  public ProbeInstallation(Context applicationContext, RestAdapter loopbackAdapter) {
      super(applicationContext, loopbackAdapter);
  }
  
  public String getImeiNumber() {
      return imeiNumber;
  }
  
  public void setImeiNumber(String imeiNumber) {
      this.imeiNumber = imeiNumber;
  }}
  </code></pre>
  
  <p>And in my MainActivity I am just using it as,</p>
  
  <pre><code>   final CustomInstallation installation =  new CustomInstallation(context, adapter);
  </code></pre>
  
  <p>Is this the way to do it or I am missing something? </p>