title: Pomelo.EntityFrameworkCore.MySql error with EF Core 3.0
body: <p>I am trying to connect to MySQL database using Pomelo.EntityFrameworkCore.MySql and EF Core 3.0</p>
  
  <p>I have followed the guide provided by Pomelo.</p>
  
  <p>When I run the web application, I can see some tables getting created successfully. However, tables with GUID as ID are getting the following error:</p>
  
  <pre><code>An error occured during migration
  MySql.Data.MySqlClient.MySqlException (0x80004005): BLOB/TEXT column 'Id' used in key specification without a key length
  </code></pre>
  
  <p>How to fix this? how to use GUID as an ID in MySql and how to workaround this error?</p>