A Problem I have after following Dockerizing Adonis with postgre tutorial

[IARI]

I followed the dockerizing adonis tutorial, but now want to actually use the postgre database with a model and have a problem with the user setup.
Thanks @hlozancic at this point for the wonderful tutorial - maybe you can also help me here?
I already posted the problem on stackoverflow and in order to make the answer available to possible future beginners facing this issue will update the respective posts with answers in case I get any.
The gist of my problem:

I created a model with a migration: node ace make:model User -m and now I want to run that migration to create the User table.
Running node ace migration:run gets me the error

[ error ] create table "adonis_schema" ("id" serial primary key,
"name" varchar(255) not null, "batch" integer not null,
"migration_time" timestamptz default CURRENT_TIMESTAMP) - permission
denied for schema public

What am I doing wrong?