Here is my code for the assignment. I was able to deploy the contract successfully and interact with every function 
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// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Pausable.sol";
import "@openzeppelin/contracts/access/AccessControlEnumerable.sol";
import "@openzeppelin/contracts/utils/Context.sol";
/**
* @dev {ERC20} token, including:
*
* - ability for holders to burn (destroy) their tokens
* - a minter role that allows for token minting (creation)
* - a pauser role that allows to stop all token transfers
* - a capper role that allows the change of the token supply cap
*
* This contract uses {AccessControl} to lock permissioned functions using the
* different roles - head to its documentation for details.
*
* The account that deploys the contract will be granted the minter, pauser, and capper
* roles, as well as the default admin role, which will let it grant both minter, pauser, and capper
* roles to other accounts.
*/
contract MyToken is Context, AccessControlEnumerable, ERC20Burnable, ERC20Pausable {
bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
bytes32 public constant PAUSER_ROLE = keccak256("PAUSER_ROLE");
bytes32 public constant CAPPER_ROLE = keccak256("CAPPER_ROLE");
uint256 private _cap;
/**
* @dev Sets token supply cap and grants `DEFAULT_ADMIN_ROLE`, `MINTER_ROLE`, `PAUSER_ROLE`, and 'CAPPER_ROLE' to the
* account that deploys the contract.
*
* See {ERC20-constructor}.
*/
constructor(string memory name, string memory symbol, uint256 cap_) ERC20(name, symbol) {
require(cap_ > 0, "ERC20Capped: cap is 0");
_cap = cap_;
_setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
_setupRole(MINTER_ROLE, _msgSender());
_setupRole(PAUSER_ROLE, _msgSender());
_setupRole(CAPPER_ROLE, _msgSender());
}
/**
* @dev Returns the cap on the token's total supply.
*/
function cap() public view virtual returns (uint256) {
return _cap;
}
/**
* @dev See {ERC20-_mint}.
*/
function _mint(address account, uint256 amount) internal virtual override {
require(ERC20.totalSupply() + amount <= cap(), "ERC20Capped: cap exceeded");
super._mint(account, amount);
}
/**
* @dev Changes the cap on the total token supply.
*
* Requirements:
*
* - the caller must have the `CAPPER_ROLE`.
*/
function recap(uint256 cap_) public virtual {
require(hasRole(CAPPER_ROLE, _msgSender()), "ERC20PresetMinterPauser: must have capper role to recap");
require(cap_ > 0, "ERC20Capped: cap is 0");
require(ERC20.totalSupply() <= cap_, "ERC20Capped: Tokens must be burned before setting a new cap this low");
_cap = cap_;
}
/**
* @dev Creates `amount` new tokens for `to`.
*
* See {ERC20-_mint}.
*
* Requirements:
*
* - the caller must have the `MINTER_ROLE`.
*/
function mint(address to, uint256 amount) public virtual {
require(hasRole(MINTER_ROLE, _msgSender()), "ERC20PresetMinterPauser: must have minter role to mint");
_mint(to, amount);
}
/**
* @dev Pauses all token transfers.
*
* See {ERC20Pausable} and {Pausable-_pause}.
*
* Requirements:
*
* - the caller must have the `PAUSER_ROLE`.
*/
function pause() public virtual {
require(hasRole(PAUSER_ROLE, _msgSender()), "ERC20PresetMinterPauser: must have pauser role to pause");
_pause();
}
/**
* @dev Unpauses all token transfers.
*
* See {ERC20Pausable} and {Pausable-_unpause}.
*
* Requirements:
*
* - the caller must have the `PAUSER_ROLE`.
*/
function unpause() public virtual {
require(hasRole(PAUSER_ROLE, _msgSender()), "ERC20PresetMinterPauser: must have pauser role to unpause");
_unpause();
}
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual override(ERC20, ERC20Pausable) {
super._beforeTokenTransfer(from, to, amount);
}
}
