I think you have looked at the tutorial from Mr. Heinemeier Hansson at least once or twice and have a similar setup.
rails new kamal_pg --css tailwind --skip-test --database=postgresql
cd kamal_pg
based on DigitalOcean guide
Create local project
local$ rails new appname -T -d postgresql
local$ rails g scaffold Story title:string body:text
local$ rails db:migrate