This buildpack is used in https://github.com/parasutcom/server repository to add tr_TR collation to test databases. heroku/ruby buildpack runs rake db:schema:load_if_ruby as part of the buildpack script, which creates database objects from schema.rb file. tr_TR collation is not included in Heroku runtime by default and table columns which use this collation cause the test setup to fail.
Heroku suggests the usage of https://github.com/heroku/heroku-buildpack-locale buildpack. However that buildpack doesn't actually install the locale system-wide as stated in heroku/heroku-buildpack-locale#13 (comment). Therefore CREATE COLLATION statement fails.
To fix this, we clone en_EN collation with the name tr_TR. This clone does not actually behave like the tr_TR collation, but we trick Postgres into believing that it does have such a collation. This way test setup does not fail.