title: Reverse a string in 0.10
body: <p>I'm having trouble reversing a string in the newest version of rust, I saw <a href="https://stackoverflow.com/questions/21975102/how-do-i-reverse-a-string-in-0-9">this</a> post but I'm still getting some errors. I'm trying to reverse a string and compare the two without any luck:</p>
  
  <pre><code>fn is_palindromic(num: int) -&gt; bool {
      let num_str = num.to_str();
      let rev_num_str = num_str.chars_rev().collect();
      if rev_num_str == num_str {
          return true;
      }else{
          return false;
      }
  
  }
  </code></pre>
  
  <p>then I receive the error:</p>
  
  <pre><code>main.rs:8:28: 8:39 error: type `collections::string::String` does not implement
  any method in scope named `chars_rev`
  main.rs:8       let rev_num_str = num_str.chars_rev();
  </code></pre>