contract Pausable is Ownable {
  event Pause();
  event Unpause();
  event PauserChanged(address indexed newAddress);


  address public pauser;
  bool public paused = false;

  /**
   * @dev Modifier to make a function callable only when the contract is not paused.
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev throws if called by any account other than the pauser
   */
  modifier onlyPauser() {
    require(msg.sender == pauser);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyPauser public {
    paused = true;
    emit Pause();
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyPauser public {
    paused = false;
    emit Unpause();
  }

  /**
   * @dev update the pauser role
   */
  function updatePauser(address _newPauser) onlyOwner public {
    require(_newPauser != address(0));
    pauser = _newPauser;
    emit PauserChanged(pauser);
  }

}
/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 * Based on openzeppelin tag v1.10.0 commit: feb665136c0dae9912e08397c1a21c4af3651ef3
 * Modifications:
 * 1) Added pauser role, switched pause/unpause to be onlyPauser (6/14/2018)
 * 2) Removed whenNotPause/whenPaused from pause/unpause (6/14/2018)
 * 3) Removed whenPaused (6/14/2018)
 * 4) Switches ownable library to use zeppelinos (7/12/18)
 * 5) Remove constructor (7/13/18)
 */
function updatePauser(address _newPauser) onlyOwner public {
  require(_newPauser != address(0));
  pauser = _newPauser;
  emit PauserChanged(pauser);
}

/**
 * @dev update the pauser role
 */