title: NSArray sort against another NSArray of strings
body: <p>I feel like this is simple but I just can't wrap my head around it. I have an array of days of the week that a user can select against:</p>
  
  <pre><code>NSArray * daysOfTheWeek = [NSArray arrayWithObjects:@"sunday", @"monday", @"tuesday", @"wednesday", @"thursday", @"friday", @"saturday", nil];
  </code></pre>
  
  <p>I as the toggle the days on and off, I'd like to sort their NSArray fo selected days against the <code>dayOfTheWeek</code> NSArray. So if a user has:</p>
  
  <pre><code>NSArray * userDays = [NSArray arrayWithObjects:@"thursday", @"monday", @"friday"];
  </code></pre>
  
  <p>I want to sort this so that its monday, thursday, friday.</p>
  
  <p>I'd seem some of the similar questions posted but none were clear enough for me to know how I could apply them to this. Could be my lack of sleep :)</p>
  
  <p>Thank you!</p>