erc20 token jossToken designed to interact with my personal website jossduff.com

jossToken.sol

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

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

/// @title
/// @author Joss Duff
/// @notice this is a personal project to set up a token for interacting with
/// and displaying messages on my website jossduff.com.  jossToken isn't intended
/// to hold any monetary value.  This is for fun.
contract JossToken is ERC20 {

  constructor() ERC20("JossToken", "JOSS") public {
    _mint(msg.sender, 1000000e18);
  }

  /// each message is an object with a address as the author and the actual message text
  struct Message {
    address author;
    string text;
  }

  /// event for front end to update and display a newly made message
  /// @param author is the address of the wallet writing the message (the wallet
  /// calling makeMessage)
  /// @param text is the actual text of the message
  event MakeMessage(address author, string text);

  // array of message objects
  Message[] public messages;

  //creates message object if the user has 1 jossToken in their wallet.
  ///@param _newMessage is the text to be displayed
  function makeMessage(string memory _newMessage) public {
    // burns a users jossToken from their wallet.  Cannot create a message if the
    // user doesn't have a jossToken
    _burn(msg.sender, 1e18);
    messages.push(Message(msg.sender, _newMessage)); //creates a message and adds it to message array
    emit MakeMessage(msg.sender, _newMessage); //updates the front end to display the newly created message
  }

  ///@dev returns the address and text of the message at the given index
  ///@param _messageIndex is the index of the message
  function getMessages(uint256 _messageIndex) public view returns(address, string memory){
    return (messages[_messageIndex].author, messages[_messageIndex].text);
  }

  //when the user presses a button the the frontend, they are given one jossToken for free.  each address can only receive ONE free joss
  //This results in a potentially infinite supply, which is fine because jossToken isn't intended to have value. It is just a test project

  //keeps track of which addresses have used the freeJoss function yet
  mapping(address => bool) private isUsed;  //bool starts as false by default

  ///@dev mints the caller 1 jossToken if the caller has not yet used this function.  Then updates the isUsed mapping to indicate that the caller has received their free jossToken
  function freeJoss() public {
    require(isUsed[msg.sender] == false); //makes sure the address hasn't used this function before
    _mint(msg.sender, 1e18); //mints a new jossToken to callers address
    isUsed[msg.sender] = true;  //updates the mapping to indicate that the caller has received their free jossToken
  }
}