Adds a management command to rebuild MPTT models

- Important to do after importing records / fixtures!
- Otherwise very strange things might happen especially when you try to use the API...

InvenTree/InvenTree/management/commands/rebuild_models.py

@@ -0,0 +1,60 @@
+"""
+Custom management command to rebuild all MPTT models
+
+- This is crucial after importing any fixtures, etc
+"""
+
+from django.core.management.base import BaseCommand
+
+
+class Command(BaseCommand):
+    """
+    Rebuild all database models which leverage the MPTT structure.
+    """
+
+    def handle(self, *args, **kwargs):
+
+        # Part model
+        try:
+            print("Rebuilding Part objects")
+
+            from part.models import Part
+            Part.objects.rebuild()
+        except:
+            print("Error rebuilding Part objects")
+
+        # Part category
+        try:
+            print("Rebuilding PartCategory objects")
+
+            from part.models import PartCategory
+            PartCategory.objects.rebuild()
+        except:
+            print("Error rebuilding PartCategory objects")
+
+        # StockItem model
+        try:
+            print("Rebuilding StockItem objects")
+
+            from stock.models import StockItem
+            StockItem.objects.rebuild()
+        except:
+            print("Error rebuilding StockItem objects")
+
+        # StockLocation model
+        try:
+            print("Rebuilding StockLocation objects")
+
+            from stock.models import StockLocation
+            StockLocation.objects.rebuild()
+        except:
+            print("Error rebuilding StockLocation objects")
+
+        # Build model
+        try:
+            print("Rebuilding Build objects")
+
+            from build.models import Build
+            Build.objects.rebuild()
+        except:
+            print("Error rebuilding Build objects")