Add Manually Run A Migration From Rails Console as a rails til

rails/manually-run-a-migration-from-rails-console.md

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+# Manually Run A Migrations From Rails Console
+
+A migration can be manually run from the rails console. In 99% of cases you are
+going to be better off using the migration CLI that Rails provides (e.g. `rails
+db:migrate`, `rails db:rollback`, etc.).
+
+If you are in a hyper-specific scenario where you need to run the `up` or the
+`down` of a migration without the migration-table check, then you'll want to
+consider this approach.
+
+First, connect to the rails console: `rails c`. Then require your migration
+file.
+
+```ruby
+> require "./db/migration/20200220181733_some_migration.rb"
+#=> true
+```
+
+You'll now have access to the `SomeMigration` constant. Create an instance of this and then run either the `up`-side of the migration:
+
+```ruby
+> SomeMigration.new.up
+#=> ... # a bunch of migration output
+```
+
+or the `down`-side of it:
+
+```ruby
+> SomeMigration.new.down
+#=> ... # a bunch of migration output
+```
+
+[source](https://stackoverflow.com/a/754316/535590)