first commit

app/models/concerns/visible.rb

@@ -0,0 +1,19 @@
+module Visible
+  extend ActiveSupport::Concern
+
+  VALID_STATUSES = ['public', 'private', 'archived']
+
+  included do
+    validates :status, inclusion: { in: VALID_STATUSES }
+  end
+
+  class_methods do
+    def public_count
+      where(status: 'public').count
+    end
+  end
+
+  def archived?
+    status == 'archived'
+  end
+end