title: Case insensitive unique constraint for Postgres + EF Core
body: <p>I am using Postgres + EF Core. I have a column called Name which I want to be unique. I have tried the following:</p>
  
  <pre><code>builder.HasIndex(s =&gt; s.Name).IsUnique();
  </code></pre>
  
  <p>but this allows "test123" and "TEST123" to be accepted. How can I add a case insensitive unique constraint with fluent api?</p>
  
  <p>Or do I just need to create a NormalizedName column and add the unique constraint to that. Seems like a lot of work every time I want to add a unique constraint to a column.</p>