title: How to create a SET-like type on postgresql
body: <p>I would like to create a column of week days such that we can select more then only one day.</p>
  
  <p>I know the enum type can do that, but it can only contain one item.</p>
  
  <p>How can I create a datatype in PostgreSQL such that I can have something that fuctions like a multiple-choice enum, just like a set on MySQL?</p>