Custom unaccent rules in heroku

We have an application running in heroku and we want to add a search feature on a field that contains greek characters and we want to make it accent agnostic. So the idea is to use postgresql's [unaccent](https://www.postgresql.org/docs/9.1/static/unaccent.html) functionality. The problem is that by default greek rules are not included at heroku and we somehow need to add them (we already have a rules file). Has anyone managed to add custom rules files at heroku, and if yes could you please share how?