title: TypeORM PostgreSQL select where JSON field equals some value
body: <p><strong>Goal:</strong>  write a select query that returns all rows where state equals "florida".</p>
  
  <p>Entity column:</p>
  
  <pre><code>  @Column({ type: 'json'})
    public address: Address;
  </code></pre>
  
  <p>Sample column value:</p>
  
  <pre><code>{"city": "miami", "state": "florida"}
  </code></pre>
  
  <p>Example query (doesn't work):</p>
  
  <pre><code>getManager().getRepository(User)
      .createQueryBuilder('user')
      .select()
      .where('user.address.state =:state', {state: "florida"})
  </code></pre>
  
  <p>Is this functionality currently supported in typeorm?  If so, how would I need to modify my where clause to return the correct rows?</p>