title: Keycloak and spring boot rest api - user specific data strategy
body: <p>Keycloak is a user federated identity solution running seperately (standalone) from other systems referencing to it (for authorization for example) having its own database. </p>
  
  <p>Question: 
  How would I reference / create user specific data in my rest api database? 
  How would I reference the user in the rest api database to have user specific data?</p>
  
  <p>Think of an table like Post</p>
  
  <p>title,
  date,
  content,
  <strong>author</strong> (here would be the reference to the user)</p>