title: Form type parameter not accessible by swagger
body: <p>I am using flasgger to provide a swagger spec for my flask app. For a particular endpoint I need form type parameters. </p>
  
  <pre><code>Update user address
  ---   
   parameters:
       - name: user_id
         in: path
         type: integer
         required: true
       - name: address
         in: form
         type: string
         required: true
         description: Address.
  </code></pre>
  
  <p>The method related to this endpoint is : </p>
  
  <pre><code>def update_address(user_id):
      approved_by = request.form.get('address')
      result = user.approve_sample(user_id, address):
      return json.dumps("OK"), 200, {'Content-Type': 'application/json; charset=utf-8'}
  </code></pre>
  
  <p>However, the address which is a form type parameter does not get updated in the database. Any suggestion why is it not registering address?</p>