title: Store accessor for nested JSON
body: <p>I have the model "Organization" that stores all information related to an organization. There is a field of type JSONB named "integrations" that stores information pertaining to all external service integrations that an organization has.</p>
  
  <p>How do I use store accessors to access information stored in nested JSON, for example : </p>
  
  <pre><code>{
   "mailchimp": {"api_key":"vsvsvef", "list_id":"12345"},
   "sendgrid" : {"username":"msdvsv", "password":"123456"}
  }
  </code></pre>
  
  <p>I know I can access mailchimp with store accessors like this : </p>
  
  <pre><code>store_accessor :integrations, :mailchimp
  </code></pre>
  
  <p>How can I easily access the api_key of mailchimp?</p>