WIP: Add light/dark theme with toggle in navbar (dark theme styling incomplete - dont care for now)

db.py

@@ -166,18 +166,22 @@ ORDER BY invocation_time DESC""", [http_function_id])
     
     def get_user(self, user_id):
         user = self.execute(
-            'SELECT id, username, password_hash, created_at FROM users WHERE id=%s', [int(user_id)], one=True)
+            'SELECT id, username, password_hash, created_at, theme_preference FROM users WHERE id=%s', [int(user_id)], one=True)
         return user
 
     def get_user_by_username(self, username):
         user = self.execute(
-            'SELECT id, username, password_hash, created_at FROM users WHERE username=%s', [username], one=True)
+            'SELECT id, username, password_hash, created_at, theme_preference FROM users WHERE username=%s', [username], one=True)
         return user
 
     def create_new_user(self, username, password_hash):
         new_user = self.execute(
-            'INSERT INTO users (username, password_hash) VALUES (%s, %s) RETURNING id, username, password_hash, created_at', [username, password_hash], commit=True, one=True)
+            'INSERT INTO users (username, password_hash, theme_preference) VALUES (%s, %s, %s) RETURNING id, username, password_hash, created_at, theme_preference', [username, password_hash, 'light'], commit=True, one=True)
         return new_user
+
+    def update_user_theme_preference(self, user_id, theme):
+        self.execute(
+            'UPDATE users SET theme_preference=%s WHERE id=%s', [theme, user_id], commit=True)
     
     def get_http_function_history(self, function_id):
         http_function_history = self.execute(