feat(follow): implement follow command for service status notifications

refactor(data-source): update entity and migration paths for consistency
fix(readme): update status feature notification system icon
delete(guilds): remove unused Guild entity
add(follow): create Follow entity for managing user notification preferences

src/commands/utility/follow.command.ts

@@ -0,0 +1,41 @@
+import { ApplicationIntegrationType, ChatInputCommandInteraction, InteractionContextType, MessageFlags, SlashCommandBuilder } from "discord.js";
+import { CommandDefinition } from "../../type";
+import { AppDataSource } from "../../data-source";
+import { Follow } from "../../entity/follow.entity";
+
+const cmd : CommandDefinition = {
+    data: new SlashCommandBuilder()
+        .setName('follow')
+        .setDescription('Enables/disables the receipt of service status notifications.')
+        .setIntegrationTypes(
+            ApplicationIntegrationType.GuildInstall,
+            ApplicationIntegrationType.UserInstall
+        )
+        .setContexts(
+            InteractionContextType.BotDM,
+            InteractionContextType.Guild,
+            InteractionContextType.PrivateChannel
+        ),
+    async execute(interaction : ChatInputCommandInteraction) {
+        const userRepo = AppDataSource.getRepository(Follow);
+
+        let follow = await userRepo.findOne({where: {user_discord: interaction.user.id}});
+        if(!follow) {
+            follow = new Follow();
+            follow.user_discord = interaction.user.id;
+            await userRepo.save(follow);
+        }
+        
+        follow.enable = !follow.enable;
+
+        await userRepo.save(follow);
+
+        await interaction.reply({content: `✅ Notification successfully ${follow.enable ? 'enabled 🔔' : 'disabled 🔕'}!`, flags: [MessageFlags.Ephemeral]});
+
+        if(follow.enable) {
+            await interaction.user.send({content: '🔔 Notifications have been successfully enabled! To disable: /follow'})
+        }
+    }
+}
+
+export default cmd;