anchor.diff:  
     @override
     Widget build(BuildContext context) {
  -    _allPages.last.child = new Column(
  +    _me.child = new Column(
           children: [
             new Text("User Name: ${_user.username}",
                 style: new TextStyle(
  
positive.code: 
      _tabController = new TabController(vsync: this, length: _allPages.length);
      _tabController.addListener(_handleTabSelection);
      _selectedPage = _allPages.last;
    }
  
    @override
  
negative.code:   void initState() {
      super.initState();
      _usernameEditingController = new TextEditingController();
      _friends = new _Page(
        label: 'Friends',
        icon: Icons.add,
        information: "You can view your friends' information or "
            "add new friends in this page.",
      );
      _kata = new _Page(
        label: 'Kata',
        icon: Icons.add_box,
        information: "You can view or add katas here, and preview them.\n"
            "submitting is not supported ATM",
      );
      _me = new _Page(
        label: 'Me',
        icon: Icons.edit,
        information: "Information about yourself on Code Wars.\n"
            "You can change your username.",
      );
      _allPages = <_Page>[_friends, _kata, _me];
      _me.onClick = () {
        showDialog(context: context, child: new SimpleDialog(
          contentPadding: new EdgeInsets.all(20.0),
          children: [
  