title: Unique constraint entity framework
body: <p>I'm using MS SQL Server 2012 + the Entity Framework 6.1.1. I have created a model using the designer. Now, I would like to add a unique to an attribute. How can I achieve this using the designer / keep the model generation?</p>
  
  <p>Edit: I do the model first approach</p>
  
  <p>Thank you</p>