Is there a way to get EF CTP5 to create an index when it creates a schema?
Update: See here for how EF 6.1 handles this (as pointed out by juFo belo
This feature should be available in the near-future via data annotations and the Fluent API. Microsoft have added it into their public backlog:
http://entityframework.codeplex.com/workitem/list/basic?keywords=DevDiv [Id=87553]
Until then, you'll need to use a seed method on a custom Initializer class to execute the SQL to create the unique index, and if you're using code-first migrations, create a new migration for adding the unique index, and use the CreateIndex and DropIndex methods in your Up and Down methods for the migration to create and drop the index.