Hi @anon29869905 - Thanks for your patch, I tried it, and it works fine 
Please find the init container logs below:
I, [2021-08-18T09:14:13.870063 #25-47434909448560] INFO -- : Can't fetch image for 'nicole.braun@zammad.org' (maybe no avatar available), http code: 422
W, [2021-08-18T09:14:14.032770 #25-47434909448560] WARN -- : Scoped order is ignored, it's forced to be batch order.
W, [2021-08-18T09:14:14.237975 #25-47434909448560] WARN -- : Scoped order is ignored, it's forced to be batch order.
I, [2021-08-18T09:14:59.027437 #25-47434909448560] INFO -- : NOTICE: install '/opt/zammad/db/addon/opensvc/20210813175700_add_org_support_contract.rb' (664)
I, [2021-08-18T09:14:59.027935 #25-47434909448560] INFO -- : NOTICE: install '/opt/zammad/db/addon/opensvc/20210813180000_add_ticket_customer_priority.rb' (664)
Performing package migrations and rebuilding assets...
I, [2021-08-18T09:15:02.596449 #42-47127785101680] INFO -- : Setting.set('models_searchable', ["Chat::Session", "KnowledgeBase::Answer::Translation", "Ticket", "Organization", "User"])
Executing all pending package migrations...
I, [2021-08-18T09:15:02.902202 #42-47127785101680] INFO -- : NOTICE: up package migration '20210813175700_add_org_support_contract.rb'
-- add_column("organizations", "support_contract", :string, {:limit=>255, :null=>true})
-> 0.0266s
I, [2021-08-18T09:15:03.077055 #42-47127785101680] INFO -- : Setting.set('app_version', "20210818091503:true")
I, [2021-08-18T09:15:03.116168 #42-47127785101680] INFO -- : NOTICE: up package migration '20210813180000_add_ticket_customer_priority.rb'
-- add_column("tickets", "customer_priority", :string, {:limit=>255, :null=>true})
-> 0.0263s
I, [2021-08-18T09:15:03.284683 #42-47127785101680] INFO -- : Setting.set('app_version', "20210818091503:true")
done.
I, [2021-08-18T09:15:06.885332 #43-47062365493620] INFO -- : Setting.set('models_searchable', ["Chat::Session", "KnowledgeBase::Answer::Translation", "Ticket", "Organization", "User"])
Yarn executable was not detected in the system.
Download Yarn at https://yarnpkg.com/en/docs/install
changing settings...
I, [2021-08-18T09:15:41.425547 #49-47400149686620] INFO -- : Setting.set('models_searchable', ["Chat::Session", "KnowledgeBase::Answer::Translation", "Ticket", "Organization", "User"])
I, [2021-08-18T09:15:42.694657 #49-47400149686620] INFO -- : Setting.set('es_url', "http://elastic:9200")
I, [2021-08-18T09:15:46.240474 #50-47223793023320] INFO -- : Setting.set('models_searchable', ["Chat::Session", "KnowledgeBase::Answer::Translation", "Ticket", "Organization", "User"])
I, [2021-08-18T09:15:47.204808 #50-47223793023320] INFO -- : Setting.set('es_index', "zammad")
I don’t know if the yarn warning is important or not ?
I look forward to see your patch merged in the docker-entrypoint.
Please ask if I can help.
Thanks a lot for your time.