title: How do you initialize jquery select2 items when you are in "tagging" mode?
body: <p>I am trying to figure out how to initialize <a href="http://ivaynberg.github.io/select2/#tags" rel="nofollow">a jquery select2 item</a> when i am in tagging mode (as i want to allow users to enter new items:</p>
  
  <p>I see this example: </p>
  
  <pre><code> $("#e12").select2({tags:["red", "green", "blue"]});
  </code></pre>
  
  <p>which works fine but I need to instantiate it with some entries already added.</p>
  
  <p>but if i want to initialize with some existing items on page load, i tried doing something like this:</p>
  
  <pre><code>   var existingEmailAddresses= ["joe@abc.com","bill@abc.com"];
  
     $("#e12").select2({
              width: "600px",
              multiple: true,
              tags:["A", "B", "C"],
              initSelection: function (element, callback) {
                  callback(existingEmailAddresses);
              }
          });
  </code></pre>
  
  <p>but that doesn't seem to be working. </p>
  
  <p>How can you initialize entrying when you are using tagging mode?  </p>
  
  <h2>Edit</h2>
  
  <p>I also want to see if there is any hook to validate new tags added. In my case I want to make sure they are valid email addresses.</p>