showing a warning if trying auto migrations with SQLite

Author: dantownsend

piccolo/apps/migrations/commands/new.py

@@ -15,6 +15,7 @@
     DiffableTable,
     SchemaDiffer,
 )
+from piccolo.engine import SQLiteEngine
 
 
 TEMPLATE_DIRECTORY = os.path.join(
@@ -140,6 +141,10 @@ def new(app_name: str, auto: bool = False):
         print("Can't find piccolo_conf")
         sys.exit(1)
 
+    if auto and isinstance(getattr(piccolo_conf, "DB"), SQLiteEngine):
+        print("Auto migrations aren't currently supported by SQLite.")
+        sys.exit(1)
+
     try:
         app_registry: AppRegistry = piccolo_conf.APP_REGISTRY
     except AttributeError: