title: Ruby on Rails: String with variable parsing
body: <p>in ruby i can build a Variable with the date like this</p>
  
  <pre><code>irb(main):004:0&gt; a = "#{Date.today}" =&gt; "2012-03-23"
  </code></pre>
  
  <p>But how can i do this with a already created string:</p>
  
  <pre><code>irb(main):005:0&gt; a = '#{Date.today}' =&gt; "\#{Date.today}"
  </code></pre>
  
  <p>The background is, that i'am storing a path with different variables in a database and i need to replace these variables at runtime.</p>
  
  <p>Thanks for any help.</p>