参考
OpenZeppelin

npm install @openzeppelin/contracts

pragma solidity >=0.4.22 <0.7.0;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20Detailed.sol";

contract TutorialToken is ERC20, ERC20Detailed {
    constructor() ERC20Detailed("Lemool", "LEM", 0) public {
        _mint(msg.sender, 10000000);
    }
}