contract Ownable {
  address public owner;

  /**
   * Ownable
   * @dev Ownable constructor sets the `owner` of the contract to sender
   */
  function Ownable() public {
    owner = msg.sender;
  }

  /**
   * ownerOnly
   * @dev Throws an error if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  /**
   * transferOwnership
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    owner = newOwner;
  }
}
/**
 * @title Ownable
 * @dev Ownable has an owner address to simplify "user permissions".
 */
function Ownable() public {
    owner = msg.sender;
  }
/**
 * Ownable
 * @dev Ownable constructor sets the `owner` of the contract to sender
 */