smartcontracts/contracts/Mintable.sol

pragma solidity ^0.4.18;

import 'zeppelin-solidity/contracts/token/StandardToken.sol';
import 'zeppelin-solidity/contracts/ownership/Ownable.sol';

contract Mintable is StandardToken, Ownable {

    event Mint(address indexed to, uint256 amount);
    event MintFinished();

    bool public mintingFinished = false;
    mapping (address => bool) private minters;

    modifier canMint() {
        require(!mintingFinished);
        _;
    }

    modifier onlyMinter() {
        require(minters[msg.sender]);
        _;
    }

    function allowMinting(address _to) onlyOwner canMint public {
        minters[_to] = true;
    }

    function denyMinting(address _to) onlyOwner public {
        delete minters[_to];
    }

    /**
     * @dev Function to mint tokens
     * @param _to The address that will receive the minted tokens.
     * @param _amount The amount of tokens to mint.
     * @return A boolean that indicates if the operation was successful.
     */
    function mint(address _to, uint256 _amount) onlyMinter canMint public returns (bool) {
        totalSupply = totalSupply.add(_amount);
        balances[_to] = balances[_to].add(_amount);
        Mint(_to, _amount);
        Transfer(0x0, _to, _amount);
        return true;
    }

    /**
     * @dev Function to stop minting new tokens.
     * @return True if the operation was successful.
     */
    function finishMinting() onlyOwner canMint public returns (bool) {
        mintingFinished = true;
        MintFinished();
        return true;
    }
}