title: forEach loop to assign new value to variables in array is not replacing value of variables
body: <p>I'm trying to loop over an array that contains three variables with a forEach loop, and change the value of each variable to a random number between 0-255.</p>
  
  <p>I've started out by giving each variable a simple value:</p>
  
  <pre><code>let rgb1 = 1;
  let rgb2 = 2;
  let rgb3 = 3;
  </code></pre>
  
  <p>And then I've put those variables into an Array:</p>
  
  <pre><code>let rgbVariables = [rgb1,rgb2,rgb3];
  </code></pre>
  
  <p>I have my function that returns a random number between 0-255</p>
  
  <pre><code>function randomColor() {
      return Math.floor((Math.random() * 255));
  }
  </code></pre>
  
  <p>And lastly my function that loops over the array</p>
  
  <pre><code>function refreshRGBNumbers() {
      rgbVariables.forEach(function(rgb) {
        rgb = randomColor();
      });
  </code></pre>
  
  <p>The refreshRGBNumbers function is called when I click a button. I have verified that the function is being called correctly, but when I check the value of the variables in the array they remain 1,2,3.</p>
  
  <p>What do I need to do here to get the function to correctly replace the array variables with the random number?</p>