for miner

<form method="post" action="login.php">              // This is login form
    <?php include('errors.php'); ?>
    <div class="input-group">
        <label>Username</label>
        <input type="text" name="username" >
    </div>
    <div class="input-group">
        <label>Password</label>
        <input type="password" name="password">
    </div>
    <div class="input-group">
        <button type="submit" class="btn" name="login_user">Login</button>
    </div>
    <p>
        Not yet a member? <a href="register.php">Sign up</a>
    </p>
  </form>


// LOGIN script----- THIS ONE WORKS on another page i made,just changed the DB and table,it always says wrong username/password
// but these are valid,also if i register new account,its set to automatically login,that works well,but once you close browser
// (loggedin and username sessions) you can never login back :x i can not find whats wrong -.- took me already 2 days looking
// at damn code but everything seems to be JUST RIGHT.

if (isset($_POST['login_user'])) {
  $username = mysqli_real_escape_string($db, $_POST['username']);
  $password = mysqli_real_escape_string($db, $_POST['password']);

  if (empty($username)) {
    array_push($errors, "Username is required");
  }
  if (empty($password)) {
    array_push($errors, "Password is required");
  }

  if (count($errors) == 0) {
    $password = md5($password);
    $query = "SELECT * FROM neonracer WHERE username='$username' AND password='$password'";
    $results = mysqli_query($db, $query);
    if (mysqli_num_rows($results) == 1) {
      $_SESSION['username'] = $username;
      $_SESSION['loggedin'] = true;
      header('location: index.php');
    }else {
        array_push($errors, "Wrong username/password combination");
    }
  }
}