title: Encrypt a string with a password in ruby
body: <p>I'd like to get some input from a user and encrypt it with a password. For example, a user gives me:</p>
  
  <pre><code>String: 'Whackabad'
  Password 'Holycrap'
  </code></pre>
  
  <p>I'd like to store their string, encrypted, but be able to decrypt the string again when the user enters their password. What is the best way to accomplish this?</p>