Add tests and fix issues

app/queries/connection.py

@@ -1,9 +1,13 @@
+from os import getenv
 
 import streamlit as st
 from sqlalchemy.sql import text
 from streamlit.connections import BaseConnection
 
-connection: BaseConnection = st.connection("sqlite")
+def connection() -> BaseConnection:
+    _connection = st.connection("sql", url=getenv('DATABASE_URL'))
+    with _connection.session as configured_session:
+        configured_session.execute(text('PRAGMA foreign_keys=ON'))
+    return _connection
+
 
-with connection.session as configure_session:
-    configure_session.execute(text('PRAGMA foreign_keys=ON'))