Update SequelizeProvider and do some other stuff

structures/PostgreSQL.js

@@ -6,7 +6,7 @@ class Database {
 		return database;
 	}
 
-	start() {
+	static start() {
 		database.authenticate()
 			.then(() => console.log('[Database] Connection has been established successfully.'))
 			.then(() => console.log('[Database] Synchronizing...'))

structures/Stats.js

@@ -1,10 +1,6 @@
 const request = require('superagent');
 
 class Stats {
-    constructor() {
-        throw new Error(`The ${this.constructor.name} class may not be instantiated.`);
-    }
-    
     static discordBots(server_count, userID) {
         return request
             .post(`https://bots.discord.pw/api/bots/${userID}/stats`)