title: how to run a one-time database change on a single user
body: <p>I have Customer and each customer has_many Properties. Customers belong to a Company. </p>
  
  <p>I'm trying to add a certain Property to each one of a single Company's Customers. I only want this change to happen once. </p>
  
  <p>I'm thinking about using a migration but it doesn't seem right to create a migration for a change that I only ever want to happen once, and only on one of my users. </p>
  
  <p>Is there a right way to do this?</p>