title: Create custom form in react-admin
body: <p>I am using <code>Edit</code> and <code>SimpleForm</code> from <code>react-admin</code>. How do I create a custom form to allow customised <code>action</code> and <code>type</code> on submit?</p>
  
  <p>App.js</p>
  
  <pre><code>&lt;Resource name="category" list={CategoryList} edit={CategoryEdit}  /&gt;
  </code></pre>
  
  <p>index.js</p>
  
  <pre><code>&lt;Edit actions={&lt;CategoryEditActions /&gt;} title={&lt;CategoryTitle /&gt;} {...props} &gt;
      &lt;SimpleForm&gt;
        &lt;DisabledInput source="id" /&gt;
        &lt;DisabledInput source="code" /&gt;
        &lt;TextInput source="name" /&gt;
     &lt;/SimpleForm&gt;
  </code></pre>
  
  <p></p>
  
  <p>Here the api call would be <code>/category/:categoryId</code> with <code>PUT</code> request. I want to modify url to <code>/category/:categoryId/test</code> with method as <code>POST</code>. Is there any way to customize this?</p>
  
  <p>I have handled this in my CustomDataProvider - </p>
  
  <pre><code> case UPDATE:
               if(resource === 'category'){
                      options.method = 'POST';
                      url = `${apiUrl}/${resource}/${params.id}/test`;
                  } else {
                      options.method = 'PUT';
                      url = `${apiUrl}/${resource}/${params.id}`;
                  }
                  break;
  </code></pre>
  
  <p>Is there any other way to handle it?</p>