feat: Add Platform APIs (#1456)

app/models/platform_app.rb

@@ -0,0 +1,16 @@
+# == Schema Information
+#
+# Table name: platform_apps
+#
+#  id         :bigint           not null, primary key
+#  name       :string           not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+class PlatformApp < ApplicationRecord
+  include AccessTokenable
+
+  validates :name, presence: true
+
+  has_many :platform_app_permissibles, dependent: :destroy
+end