Add Set DateTime To Include Time Zone In Migrations as a Rails TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
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@@ -1003,6 +1003,7 @@ _1486 TILs and counting..._
 - [Select Value For SQL Counts](rails/select-value-for-sql-counts.md)
 - [Serialize With fast_jsonapi In A Rails App](rails/serialize-with-fast-jsonapi-in-a-rails-app.md)
 - [Set A Timestamp Field To The Current Time](rails/set-a-timestamp-field-to-the-current-time.md)
+- [Set DateTime To Include Time Zone In Migrations](rails/set-datetime-to-include-time-zone-in-migrations.md)
 - [Set default_url_options For Entire Application](rails/set-default-url-options-for-entire-application.md)
 - [Set Schema Search Path](rails/set-schema-search-path.md)
 - [Set Statement Timeout For All Postgres Connections](rails/set-statement-timeout-for-all-postgres-connections.md)

rails/set-datetime-to-include-time-zone-in-migrations.md

@@ -0,0 +1,45 @@
+# Set Datetime To Include Time Zone In Migrations
+
+When using Rails and PostgreSQL, your migrations will contain DSL syntax like
+`t.datetime` and `t.timestamps` which will produce columns using the
+`timestamp` (`without time zone`) Postgres data type.
+
+While reading [A Simple Explanation of Postgres' <code>Timestamp with Time
+Zone</code>](https://naildrivin5.com/blog/2024/10/10/a-simple-explanation-of-postgres-timestamp-with-time-zone.html),
+I learned that there is a way to configure your app to instead use
+`timestamptz` by default. This data type is widely recommended as a good
+default, so it is nice that we can configure Rails to use it.
+
+First, add these lines to a new initializer (`config/initializers/postgres.rb`)
+file.
+
+```ruby
+require "active_record/connection_adapters/postgresql_adapter"
+ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.datetime_type = :timestamptz
+```
+
+Alternatively, you can configure this via `config/application.rb` per the
+[Configuring ActiveRecord
+docs](https://guides.rubyonrails.org/configuring.html#activerecord-connectionadapters-postgresqladapter-datetime-type).
+
+Then, if you have a new migration like the following:
+
+```ruby
+class AddEventsTable < ActiveRecord::Migration[7.2]
+  def change
+    create_table :events do |t|
+      t.string :title
+      t.text :description
+      t.datetime :start_time
+      t.datetime :end_time
+      t.timestamps
+    end
+  end
+end
+```
+
+you can expect to have four `timestamptz` columns, namely `start_time`,
+`end_time`, `created_at`, and `updated_at`.
+
+Here is the [Rails PR](https://github.com/rails/rails/pull/41084) that adds
+this config option.