Add an 'add_document' method to the Folder class

apps/folders/models.py

@@ -32,6 +32,10 @@ class Folder(models.Model):
         folder_document = self.folderdocument_set.get(document=document)
         folder_document.delete()
     
+    def add_document(self, document):
+        folder_document, created = FolderDocument.objects.get_or_create(folder=self, document=document)
+        return created
+
     class Meta:
         unique_together = ('title', 'user')
         ordering = ('title',)