title: merging and appending hashes in ruby
body: <p>I have two hashes like this </p>
  
  <pre><code>h1 = {:a=&gt;[:client]}
  h2 = {:a=&gt;[:user]}
  </code></pre>
  
  <p>and I would love to merge them together but keep the values from both hashes like:</p>
  
  <pre><code>{:a=&gt;[:user, :client]}
  </code></pre>
  
  <p>I tried the merge method but it remove one value and keep only one. I am using <code>ruby 2.2</code></p>