Add circle posts history support (#18)

* Wip: make web backend

* Wip: keep statuses if edit circle

* Wip: Add circle history page and record circle posts

* Add circle post to history in web ui when post

* Add test

db/migrate/20230923103430_create_circle_statuses.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require Rails.root.join('lib', 'mastodon', 'migration_helpers')
+
+class CreateCircleStatuses < ActiveRecord::Migration[7.0]
+  include Mastodon::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  def change
+    safety_assured do
+      create_table :circle_statuses do |t|
+        t.belongs_to :circle, null: true, foreign_key: { on_delete: :cascade }
+        t.belongs_to :status, null: false, foreign_key: { on_delete: :cascade }
+        t.datetime :created_at, null: false
+        t.datetime :updated_at, null: false
+      end
+
+      add_index :circle_statuses, [:circle_id, :status_id], unique: true
+    end
+  end
+end