Add some comments

config.py

@@ -14,6 +14,9 @@ class DBConfig:
 
 
 def read_db_config() -> DBConfig:
+    """
+    Reads the DB connection parameters from the config file.
+    """
     config_dir = Path(platformdirs.user_config_dir(constants.APP_NAME, ensure_exists=True))
     config_path = config_dir / constants.DB_CONFIG_FILE_NAME
 

constants.py

@@ -1,3 +1,6 @@
+# This file should only contain constants that we use throughout the program,
+# i.e. stuff that might be changed at some point, but not changed on user-level
+
 APP_NAME = 'hanabi-league'
 DB_CONFIG_FILE_NAME = 'config.yaml'