Draft: read previous category tree from env

Related to:

• management#821 (closed)
• management#871 (closed)

Reimplement incremental mode reading "PREVIOUS_CATEGORY_TREE" env variable instead of rebuilding category tree only from existing datasets in json-data

convert.py

@@ -134,7 +134,8 @@ def build_category_json(datasets_info, previous_category_tree=None):
     category_info = []
     for category_code in sorted(du.CATEGORY_LABELS):
 
-        # Don't  category
+        # Don't append the category if it doesn't appear
+        # in previous category tree and there are no matching datasets
         if (
             category_code not in datasets_category_codes
             and category_code not in previous_category_map