support setting DJANGO_PROJECT_FOLDER via --project-root-path

settings file can be located in a subdirectory of the project

README.rst

@@ -43,7 +43,7 @@ Add the migration linter your ``INSTALLED_APPS``:
     ]
 
 
-``python manage.py lintmigrations [GIT_COMMIT_ID] [--ignore-name-contains IGNORE_NAME_CONTAINS] [--include-apps INCLUDE_APPS [INCLUDE_APPS ...] | --exclude-apps EXCLUDE_APPS [EXCLUDE_APPS ...]]``
+``python manage.py lintmigrations [GIT_COMMIT_ID] [--ignore-name-contains IGNORE_NAME_CONTAINS] [--include-apps INCLUDE_APPS [INCLUDE_APPS ...] | --exclude-apps EXCLUDE_APPS [EXCLUDE_APPS ...]] [--project-root-path DJANGO_PROJECT_FOLDER]``
 
 ================================================== ===========================================================================================================================
                    Parameter                                                                            Description
@@ -59,6 +59,7 @@ Add the migration linter your ``INSTALLED_APPS``:
 ``--no-cache``                                     Don't use a cache.
 ``--applied-migrations``                           Only lint migrations that are applied to the selected database. Other migrations are ignored.
 ``--unapplied-migrations``                         Only lint migrations that are not yet applied to the selected database. Other migrations are ignored.
+``--project-root-path DJANGO_PROJECT_FOLDER``      An absolute or relative path to the django project.
 ================================================== ===========================================================================================================================
 
 Examples

django_migration_linter/management/commands/lintmigrations.py

@@ -46,6 +46,9 @@ class Command(BaseCommand):
                 "Defaults to default"
             ),
         )
+        parser.add_argument(
+            "--project-root-path", type=str, nargs="?", help="django project root path"
+        )
 
         cache_group = parser.add_mutually_exclusive_group(required=False)
         cache_group.add_argument(
@@ -86,9 +89,12 @@ class Command(BaseCommand):
         )
 
     def handle(self, *args, **options):
-        settings_path = os.path.dirname(
+        if options["project_root_path"]:
-            import_module(os.getenv("DJANGO_SETTINGS_MODULE")).__file__
+            settings_path = options["project_root_path"]
-        )
+        else:
+            settings_path = os.path.dirname(
+                import_module(os.getenv("DJANGO_SETTINGS_MODULE")).__file__
+            )
 
         if options["verbosity"] > 1:
             logging.basicConfig(format="%(message)s", level=logging.DEBUG)