feat(backend): add the db connection

backend/database/connection.py

@@ -0,0 +1,24 @@
+import sqlite3
+from typing import List, Tuple
+
+class DatabaseConnection:
+    def __init__(self, db_name: str):
+        self.conn = sqlite3.connect(db_name)
+        self.cursor = self.conn.cursor()
+
+    def close_connection(self):
+        self.conn.close()
+
+    def execute_query(self, query: str, params: Tuple = None):
+        if params:
+            self.cursor.execute(query, params)
+        else:
+            self.cursor.execute(query)
+        self.conn.commit()
+
+    def execute_query_with_return(self, query: str, params: Tuple = None):
+        if params:
+            self.cursor.execute(query, params)
+        else:
+            self.cursor.execute(query)
+        return self.cursor.fetchall()