Add specs configuration

spec/dummy/app/models/post.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class Post < ApplicationRecord
+  enum state: %i[available unavailable arriving]
+
+  belongs_to :author, inverse_of: :posts, autosave: true
+
+  has_one :author_profile, through: :author, source: :profile
+
+  has_many :post_tags, inverse_of: :post, dependent: :destroy
+  has_many :tags, through: :post_tags
+
+  validates :title, allow_blank: false, presence: true
+
+  scope :published, -> { where(published: true) }
+  scope :recents, -> { where('created_at > ?', Date.today - 8.month) }
+
+  def short_title
+    title.truncate 10
+  end
+
+  def upper_title
+    title.upcase
+  end
+end