title: How to add gradient fill on bar chart?
body: <p>I have data frame (<code>df</code>), with column: <code>asdfg</code> (character) and <code>NUMERIC</code> (numeric). </p>
  
  <p>Using </p>
  
  <pre><code>ggplot(df, aes(x = asdfg, y = NUMERIC)) + geom_bar(stat = "identity", fill= "red")
  </code></pre>
  
  <p>I made something like that:</p>
  
  <p><img src="https://i.stack.imgur.com/dSjR5.png" alt="enter image description here"></p>
  
  <p>Now I want to get bar chart like:</p>
  
  <p><img src="https://i.stack.imgur.com/fAorF.png" alt="enter image description here"></p>
  
  <p>I've no idea how to do that. I've tried using <code>scale_colour_gradient2</code> but it doesn't work (probably I did it wrong).</p>