feat(auth): implement user authentication system

backend/node_modules/mysql2/lib/commands/quit.js

@@ -0,0 +1,29 @@
+'use strict';
+
+const Command = require('./command.js');
+const CommandCode = require('../constants/commands.js');
+const Packet = require('../packets/packet.js');
+
+class Quit extends Command {
+  constructor(callback) {
+    super();
+    this.onResult = callback;
+  }
+
+  start(packet, connection) {
+    connection._closing = true;
+    const quit = new Packet(
+      0,
+      Buffer.from([1, 0, 0, 0, CommandCode.QUIT]),
+      0,
+      5
+    );
+    if (this.onResult) {
+      this.onResult();
+    }
+    connection.writePacket(quit);
+    return null;
+  }
+}
+
+module.exports = Quit;