title: How can I solve problem with typescript and @storybook/addon-knobs
body: <p>I want to use <em>@storybook/addon-knobs</em> method <em>text</em>. I set this type in my code <code>type ButtonColor = 'primary' | 'transparent' | 'light'</code> and I wanna write text in input (text from addon):</p>
  <pre><code>const ButtonStories = () =&gt; (
    &lt;Button
      borderRadius={16}
      color={text('color', 'primary')}
    &gt;
      {text('value', 'Button')}
    &lt;/Button&gt;
  )
  </code></pre>
  <p>But when I use it I get as error:</p>
  <blockquote>
  <p>Type 'string' is not assignable to type 'primary' | 'light' |
  'transparent' | undefined</p>
  </blockquote>
  <p>How can I fix it?</p>