FEATURE: make the use_email_for_username_and_name_suggestions setting visible and on by default on existing sites (#15751)

db/migrate/20220130192155_set_use_email_for_username_and_name_suggestions_on_existing_sites.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class SetUseEmailForUsernameAndNameSuggestionsOnExistingSites < ActiveRecord::Migration[6.1]
+  def up
+    result = execute <<~SQL
+      SELECT created_at
+      FROM schema_migration_details
+      ORDER BY created_at
+      LIMIT 1
+    SQL
+
+    # make setting enabled for existing sites
+    if result.first['created_at'].to_datetime < 1.hour.ago
+      execute <<~SQL
+        INSERT INTO site_settings(name, data_type, value, created_at, updated_at)
+        VALUES('use_email_for_username_and_name_suggestions', 5, 't', NOW(), NOW())
+        ON CONFLICT (name) DO NOTHING
+      SQL
+    end
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end