db: migrate ActiveStorage to Rails 6.1

db/migrate/20210318090000_add_service_name_to_active_storage_blobs.active_storage.rb

@@ -0,0 +1,20 @@
+# This migration comes from active_storage (originally 20190112182829)
+class AddServiceNameToActiveStorageBlobs < ActiveRecord::Migration[6.0]
+  def up
+    unless column_exists?(:active_storage_blobs, :service_name)
+      add_column :active_storage_blobs, :service_name, :string
+
+      if (configured_service = ActiveStorage::Blob.service.name)
+        # rubocop:disable DS/Unscoped
+        ActiveStorage::Blob.unscoped.update_all(service_name: configured_service)
+        # rubocop:enable DS/Unscoped
+      end
+
+      change_column :active_storage_blobs, :service_name, :string, null: false
+    end
+  end
+
+  def down
+    remove_column :active_storage_blobs, :service_name
+  end
+end

db/migrate/20210318090001_create_active_storage_variant_records.active_storage.rb

@@ -0,0 +1,14 @@
+# This migration comes from active_storage (originally 20191206030411)
+# rubocop:disable Rails/CreateTableWithTimestamps
+class CreateActiveStorageVariantRecords < ActiveRecord::Migration[6.0]
+  def change
+    create_table :active_storage_variant_records do |t|
+      t.belongs_to :blob, null: false, index: false
+      t.string :variation_digest, null: false
+
+      t.index [:blob_id, :variation_digest], name: "index_active_storage_variant_records_uniqueness", unique: true
+      t.foreign_key :active_storage_blobs, column: :blob_id
+    end
+  end
+end
+# rubocop:enable Rails/CreateTableWithTimestamps