title: Regular expression in ruby to get all vowels in string
body: <p>How do you get all occurrences of vowels in a string along with its index?</p>
  
  <blockquote>
    <p>Example: str="rohan"
    I want a result like { 1=>'o', 3 => 'a' }</p>
  </blockquote>
  
  <p>Is there any method in ruby to do so or do I have to write a method for that?</p>