title: KeychainItemWrapper linking error
body: <p>I just tried to use the KeychainItemWrapper provided by Apple, but I'm getting a linking error each time:</p>
  
  <blockquote>
    <p>Undefined symbols for architecture i386:
      "_OBJC_CLASS_$_KeychainItemWrapper", referenced from:
          objc-class-ref in DataModel.o</p>
    
    <p>ld: symbol(s) not found for architecture i386
    clang: error: linker command failed with exit code 1 (use -v to see invocation)</p>
  </blockquote>
  
  <p>I've included the Security framework and checked why Apple included in the Xcode project, but I can't seem to find what else is going wrong.</p>
  
  <pre><code>_keychain = [[KeychainItemWrapper alloc] initWithIdentifier:@"com.website.project" accessGroup:nil];
  [_keychain setObject:_username forKey:(id)kSecAttrAccount];
  [_keychain setObject:_password forKey:(id)kSecValueData];
  </code></pre>
  
  <p>I also added "com.website.project" to my Keychain Access Groups.</p>