title: Android GCM Sender_ID usage
body: <p>Confused about this parameter usage.  I followed the steps for GCM setup and obtained my <code>senderID</code>.  Now do I just hard code this in my application as below?</p>
  
  <pre><code>intent.putExtra("sender", senderID);
  </code></pre>
  
  <p>I mean is the <code>senderID</code> the same for all installations of my client and server?  If not, how can a user setup his <code>senderID</code> when he installs the app?</p>