title: Convert string to decimal number in ruby
body: <p>I need to work with decimals.
  In my program, the user need to put a number with decimals to convert that number.</p>
  
  <p>The problem is: If I try to convert the argument into a number I get a integer without decimals.</p>
  
  <pre><code># ARGV[0] is: 44.33
  
  size = ARGV[0]
  
  puts size.to_i
  # size is: 44
  # :(
  </code></pre>