add active storage

db/migrate/20210804233306_create_active_storage_tables.active_storage.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+# This migration comes from active_storage (originally 20170806125915)
+class CreateActiveStorageTables < ActiveRecord::Migration[5.2]
+  def change
+    create_table(:active_storage_blobs) do |t|
+      t.string(:key,          null: false)
+      t.string(:filename,     null: false)
+      t.string(:content_type)
+      t.text(:metadata)
+      t.string(:service_name, null: false)
+      t.bigint(:byte_size,    null: false)
+      t.string(:checksum,     null: false)
+      t.datetime(:created_at, null: false)
+
+      t.index([:key], unique: true)
+    end
+
+    create_table(:active_storage_attachments) do |t|
+      t.string(:name, null: false)
+      t.references(:record,   null: false, polymorphic: true, index: false)
+      t.references(:blob,     null: false)
+
+      t.datetime(:created_at, null: false)
+
+      t.index(
+        [:record_type, :record_id, :name, :blob_id],
+        name: "index_active_storage_attachments_uniqueness",
+        unique: true
+      )
+      t.foreign_key(:active_storage_blobs, column: :blob_id)
+    end
+
+    # rubocop:disable Rails/CreateTableWithTimestamps
+    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
+    # rubocop:enable Rails/CreateTableWithTimestamps
+  end
+end