Create part label tables at boot

app/services/schema_upgrade.py

@@ -37,6 +37,8 @@ ADDITIVE_COLUMNS = {
 NEW_TABLES = (
     'app.models.instruction_fetch.InstructionFetchJob',
     'app.models.api_call.BricksetApiCall',
+    'app.models.part_label.PartCategory',
+    'app.models.part_label.PartLabel',
 )