title: How do I create a secondary index in my Amplify schema?
body: <p>In one of the tables being generated by my amplify schema, I want to create an index to be used by a lambda to query; not actually anything in GraphQL.  </p>
  
  <p>I've tried adding a <code>@connection</code> directive, but then get <code>Could not find an object type named String.</code></p>
  
  <p>I'd rather do it in a config file so I can commit to git.  What is the appropriate way to do this?</p>