title: Add previous value to each hash value
body: <p>I have a hash with integer values:</p>
  
  <pre><code>h = {
    a: 1,
    b: 1,
    c: 1,
    d: 2,
    e: 2,
  }
  </code></pre>
  
  <p>I need to add <code>100</code> to the first value, and for the second value and on, I need to add the preceding value to the original value to get:</p>
  
  <pre><code>{
    a: 101,
    b: 102,
    c: 103,
    d: 105,
    e: 107,
  }
  </code></pre>
  
  <p>Is there a good way to achieve this?</p>