title: swagger 3: schema for dictionary of dictionaries
body: <p>I want to model a schema where response is dictionary of dictionaries:</p>
  
  <pre><code>{
    'id1': {
      'type': 'type1',
      'active': true,
    }, 
    'id2': {
      'type': 'type2',
      'active': false,
    },
    ... 
    ... 
  }
  </code></pre>
  
  <p>I have defined:</p>
  
  <pre><code>components:
    schemas:
      accountData:
        type: object
        required:
          - type
          - active
        properties:
          type:
            type: string
          active:
            type: boolean
  
      accounts:
        type: object
        additionalProperties:
          type: object
          properties:
            account-id:
              type: object
              $ref: '#/components/schemas/accountData'
  </code></pre>
  
  <p>Now I want to define '#/components/schemas/accounts' which is a repeating dictionary of '#/components/schemas/account'.</p>
  
  <p>I am very new to OpenApi 3, I am unable to figure out how to do it.</p>