best way to add synonyms to an index

[naarani]

To add synonyms, if the configuration file is smaller then 1Mbyte it's possible to use config maps. However if the file is bigger then 1Mbyte, it is not possibible to use config maps.

The file should be under config directory of elasticsearch (eventually in a subdiretory).
What could be a way to manage the problem else then adding it to the Docker image?

NB
ref to synonyms in elastic
https://www.elastic.co/guide/en/elasticsearch/reference/current/analysis-synonym-tokenfilter.html