Add Add timestamptz Columns With The Migration DSL as a rails til

README.md

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 - [Add A Foreign Key Reference To A Table](rails/add-a-foreign-key-reference-to-a-table.md)
 - [Add A Reference Column With An Index](rails/add-a-reference-column-with-an-index.md)
 - [Add React With Webpacker To A New Rails App](rails/add-react-with-webpacker-to-a-new-rails-app.md)
+- [Add timestamptz Columns With The Migration DSL](rails/add-timestamptz-columns-with-the-migration-dsl.md)
 - [Access Secrets In A Rails 5.2 App](rails/access-secrets-in-a-rails-5-2-app.md)
 - [ActiveRecord Query For This Or That](rails/active-record-query-for-this-or-that.md)
 - [Advance The Date](rails/advance-the-date.md)

rails/add-timestamptz-columns-with-the-migration-dsl.md

@@ -0,0 +1,41 @@
+# Add timestamptz Columns With The Migration DSL
+
+The Rails migration DSL comes with the
+[`t.timestamps`](https://edgeapi.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/TableDefinition.html#method-i-timestamps)
+method. This allows you to add the `created_at` and `updated_at` timestamp
+columns that are standard for most models in Rails apps.
+
+```ruby
+create_table :posts do |t|
+  t.string :title, null: false
+  # ...
+
+  t.timestamps
+end
+```
+
+With a PostgreSQL database, this will result in a `posts` table that has
+`created_at` and `updated_at` columns that are of type `timestamp(6) without
+time zone`.
+
+I'd prefer to use timestamp columns that include a time zone offset. PostgreSQL
+supports this with its [`timestamptz` (`timestamp with time
+zone`)](https://www.postgresql.org/docs/current/datatype-datetime.html) data
+type.
+
+We can tell the Rails DSL to generate this type of column by abondoning the
+`t.timestamps` method and instead creating custom columns with
+[`t.column`](https://edgeapi.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/TableDefinition.html#method-i-column).
+
+```ruby
+create_table :posts do |t|
+  t.string :title, null: false
+  # ...
+
+  t.column :created_at, :timestamptz, null: false
+  t.column :updated_at, :timestamptz, null: false
+end
+```
+
+It is a little less convenient than the `t.timestamps` helper, but it is nice
+to know we can have a little more control over the data type.