pragma solidity >=0.5.0 <0.6.0;

import "./Token_V0.sol";


/**
 * @title Token_V1
 * @dev Version 1 of a token to show upgradeability.
 * The idea here is to extend a token behaviour providing burnable functionalities
 * in addition to what's provided in version 0
 */
contract Token_V1 is Token_V0 {
    event Burn(address indexed burner, uint256 value);

    function burn(uint256 value) public {
        require(balanceOf(msg.sender) >= value);
        _balances[msg.sender] = _balances[msg.sender].sub(value);
        _totalSupply = _totalSupply.sub(value);
        emit Burn(msg.sender, value);
    }
}