title: Automapper append source list items to destination list
body: <p>I am trying to map <code>List&lt;string&gt;</code> property but I want in destination object to always have default value. On the source object list can be empty or it can contain other values. </p>
  
  <p>If the list is empty then the Destination property will contain only the default value that is defined in the constructor.</p>
  
  <p>If the list contains some data, then Source values should be appended in the list.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>    List&lt;string&gt; _accessRights;
      public User()
      {
          _accessRights = new List&lt;string&gt;() { "user" };
      }
      public List&lt;string&gt; AccessRights
      {
          get { return _accessRights; }
          set { _accessRights = value; }
      }
  </code></pre>
  
  <p>Here is the example how I would use it.</p>
  
  <pre><code>UserModel user = new UserModel() { access_rights = new List&lt;string&gt;() { "power_user", "admin" } };
          User dbUser = Mapper.Map&lt;User&gt;(user);
  </code></pre>
  
  <p>As a result I would like to have <code>user, power_user, admin</code> saved in the database. 
  If the <code>access_rights</code> was <code>null</code> then I would expect to have only <code>user</code>.</p>
  
  <p>Is that possible?</p>