Fix pg_isready for migration_job

[gawsoftpl]

Description
After setting up chatwoot today, my instance was not able to start. I am using the built-in bitnami postgrsql db.
As it turned out, the db initialization (migration job) was stuck, because the pg_isready command in the init container didn't succeed. It just printed out no attempt, which suggests an invalid configuration (see https://www.postgresql.org/docs/current/app-pg-isready.html).

Solution
After adding the -U postgres parameter manually, the command exited with 0 and the migrations where able to run

Same issue in another pull request #156

[knorr3]

Hello @gawsoftpl,
why are you "stealing" my pull request? You just copied my entire description and code changes.

[gawsoftpl]

I double this pr because nobody answer for your issue, I dont know that this project is alive? Did you write to owner of this project?