[rewrite] Work on user registration, slightly polished schemas structure

backend/app/database/manager.py

@@ -12,20 +12,20 @@ class DatabaseManager():
 
     _instance: 'DatabaseManager' = None
 
-    def __new__(cls, *args, **kwargs):
+    def __new__(cls, mysql_user: str, mysql_password: str, mysql_host: str, mysql_port: int, mysql_db_name: str):
         if cls._instance is None:
             cls._instance = super().__new__(cls)
         return cls._instance
 
 
-    def __init__(self, mysql_user: str, mysql_password: str, mysql_host: str, mysql_port: str, mysql_db_name: str) -> None:
+    def __init__(self, mysql_user: str, mysql_password: str, mysql_host: str, mysql_port: int, mysql_db_name: str) -> None:
         self.logger = logging.getLogger(__name__)
         self.logger.info("Reading database config")
         self.engine = create_engine('mysql+mysqlconnector://%s:%s@%s:%s/%s' % (
             mysql_user,
             mysql_password,
             mysql_host,
-            mysql_port,
+            str(mysql_port),
             mysql_db_name),
             pool_pre_ping=True)
         self.test_connection()