title: Merge multiple array in lodash
body: <blockquote>
    <p>I want to merge these array in to single array with unique value.
    don't want repeated values.</p>
  </blockquote>
  
  <pre><code>0:Array(2) ["General Fitness", "Health &amp; Fitness"]
  1:Array(2) ["Cardiovascular", "Meditation"]
  2:Array(3) ["Health &amp; Fitness", "Cardiovascular", "General Fitness"]
  3:Array(1) ["Cardiovascular"]
  </code></pre>
  
  <blockquote>
    <p>I am expecting this answer:</p>
  </blockquote>
  
  <pre><code>["General Fitness", "Health &amp; Fitness", "Cardiovascular", "Meditation"]
  </code></pre>