private boolean logout(LogoutMessage logoutMessage) {
    User targetUser = userManager.getUserByUsername(logoutMessage.getUser().getUsername());
    if (targetUser != null) {
      userManager.removeUser(targetUser);
      // TEST MESSAGE
      System.out.println("User - " + targetUser.getUsername() + " - logged out! Logged in users ("
          + userManager.getNumberOfUsers() + "): " + userManager.getListOfUsers());
      notifyFriendsThatUserWentOffline(logoutMessage.getUser());
      return true;
    }
    return false;
  }