Store Transcriptions in local cache

Depends on !67 (merged)

Closes #43 (closed)

tests/test_elements_worker/test_transcriptions.py

@@ -169,7 +169,7 @@ def test_create_transcription(responses, mock_elements_worker_with_cache):
         "score": 0.42,
     }
 
-    # Check that created transcriptions and elements were properly stored in SQLite cache
+    # Check that created transcription was properly stored in SQLite cache
     cache_path = f"{CACHE_DIR}/db.sqlite"
     assert os.path.isfile(cache_path)