AccountRegistry

contract AccountRegistry is Ownable {
  mapping(address => bool) public accounts;
  mapping(address => bool) public invites;

  address public registryAdmin;

  event AccountCreated(address indexed newUser);
  event Invite(address indexed newUser);

  function AccountRegistry() public {
    accounts[owner] = true;
    registryAdmin = owner;
  }

  function setRegistryAdmin(address _newRegistryAdmin) public onlyOwner nonZero(_newRegistryAdmin) {
    registryAdmin = _newRegistryAdmin;
  }

  function createAccount(address _newUser) public onlyRegistryAdmin {
    require(!accounts[_newUser]);
    createAccountFor(_newUser);
  }

  function createAccountFor(address _newUser) private {
    accounts[_newUser] = true;
    emit AccountCreated(_newUser);
  }

  function inviteUser(address _newUser) public nonZero(_newUser) {
    requie(accounts[msg.sender]);
    require(!accounts[_newUser]);
    requie(!invites[_newUser]);
    invites[_newUser] = true;
    emit Invite(_newUser);
  }

  function acceptInvite() public {
    require(invites[msg.sender]);
    require(!accounts[msg.sender]);
    createAccountFor(msg.sender);
  }

  modifier nonZero(address _address) {
    require(_address != 0);
    _;
  }

  modifier onlyRegistryAdmin {
    require(msg.sender == registryAdmin);
    _;
  }


}