Rails app not following the timezone configured in config/application.rb - ruby-on-rails

Question

I'm new to configuring timezones and confused about a few points. Any advice on the correct configuration would be appreciated.
My understanding is that it's best practice to store all timestamps as UTC in the DB (I'm using PostgreSQL). On the other hand, in the actual app, I'd like to see the timestamps in my local timezone (JST +9:00).
I've configured config/application.rb like this:
module MyApp
class Application < Rails::Application
config.load_defaults 5.2
config.time_zone = 'Tokyo'
end
end
However, I'm not sure it's configured correctly, because I'm getting mixed results in the rails console. Time.zone and Time.now tell me the timezone is set to JST, but the created_at and updated_at timestamps are rendered as UTC when I do User.first.
User.first
#=> #<User id: 1, first_name: "Bob", last_name: "Smith", created_at: "2019-04-09 08:54:30", updated_at: "2019-04-09 08:54:30">
But then, the time is rendered as JST if I specifically ask for the created_at time:
User.first.created_at
#=> Tue, 09 Apr 2019 17:54:30 JST +09:00
Why are the timestamps being rendered as UTC unless I specifically ask for the time itself? Is this normal? The same phenomenon is happening for DateTime columns in my other tables as well.

Answer 1

All your dates seems to be the same, it's just how they are represented on different contexts.
This:
User.first
#=> #<User id: 1, first_name: "Bob", last_name: "Smith", created_at: "2019-04-09 08:54:30", updated_at: "2019-04-09 08:54:30">
renders the result of .inspect
This:
User.first.created_at
#=> Tue, 09 Apr 2019 17:54:30 JST +09:00
is the console guessing you want the date formated with the current time zone.
You could force some representation being explicit
User.first.created_at.to_formatted_s(:db) #should print the same as you see on the inspect
I18n.localize(User.first.created_at) #should localize the date with the default date format
I18n.localize(USer.first.created_at, format: :something) #should localize the date as the format you defined as ":something" on your locale file