pragma solidity ^0.6.0;

import "@openzeppelin/contracts/access/AccessControl.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract MyToken is ERC20, AccessControl {
    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
    bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");

    constructor() public ERC20("MyToken", "TKN") {
        // Grant the contract deployer the default admin role: it will be able
        // to grant and revoke any roles
        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);

    function mint(address to, uint256 amount) public {
        require(hasRole(MINTER_ROLE, msg.sender), "Caller is not a minter");
        _mint(to, amount);

    function burn(address from, uint256 amount) public {
        require(hasRole(BURNER_ROLE, msg.sender), "Caller is not a burner");
        _burn(from, amount);