Add user slash command

commands/testing/user.js

@@ -0,0 +1,12 @@
+const { SlashCommandBuilder } = require('discord.js');
+
+module.exports = {
+    data: new SlashCommandBuilder()
+        .setName('user')
+        .setDescription('Provides information about the user.'),
+    async execute(interaction) {
+        // interaction.user is the object representing the user who ran the command
+        // interaction.member is the GuildMember object, which represents the user in the specific guild
+        await interaction.reply('This command was run by ${interaction.user.username}, who joined on ${interaction.member.joinedAt}.');
+    },
+};