pragma solidity ^0.4.17;

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control 
 * functions, this simplifies the implementation of "user permissions". 
 */
contract Ownable {
  address public owner;


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


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


  /**
   * @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 {
    if (newOwner != address(0)) {
      owner = newOwner;
    }
  }

}