Merge parents caches into the current task one

Closes #45 (closed)

arkindex_worker/cache.py

@@ -60,6 +60,11 @@ class CachedTranscription(Model):
         table_name = "transcriptions"
 
 
+# Add all the managed models in that list
+# It's used here, but also in unit tests
+MODELS = [CachedElement, CachedTranscription]
+
+
 def init_cache_db(path):
     db.init(
         path,
@@ -77,7 +82,7 @@ def create_tables():
     """
     Creates the tables in the cache DB only if they do not already exist.
     """
-    db.create_tables([CachedElement, CachedTranscription])
+    db.create_tables(MODELS)
 
 
 def merge_parents_cache(parent_ids, current_database, data_dir="/data"):