title: Flattening Postgres nested JSONB column
body: <p>I'm looking to see how to flatten data nested in a JSONB column.
  As an example, say we have the table users with user_id(int) and siblings(JSONB)</p>
  
  <p>With rows like:</p>
  
  <pre><code>id | JSONB
  ---------------------
  1  | {"brother": {"first_name":"Sam", "last_name":"Smith"}, "sister": {"first_name":"Sally", "last_name":"Smith"}
  2  | {"sister": {"first_name":"Jill"}}
  </code></pre>
  
  <p>I'm looking for a query that will return a response like:</p>
  
  <pre><code>id | sibling   | first_name | last_name
  -------------------------------------
  1  | "brother" | "Sam"      | "Smith"
  1  | "sister"  | "Sally"    | "Smith"
  2  | "sister"  | "Jill"     | null
  </code></pre>