add new tables and models for join through association

spec/support/models.rb

@@ -129,3 +129,21 @@ class Category < ActiveRecord::Base
   has_many :tags
   belongs_to :categoriable, polymorphic: true
 end
+
+class Player < ActiveRecord::Base
+  include PgSearchable
+  pg_search fields: %i[players.id players.name players.value], default_fields: [:name], fields_mappings: { tag: 'ptags.value' }, joins: [:ptags]
+  has_many :taggings
+  has_many :ptags, through: :taggings
+end
+
+class Ptag < ActiveRecord::Base
+  self.table_name = :ptags
+  has_many :taggings
+  has_many :players, through: :taggings
+end
+
+class Tagging < ActiveRecord::Base
+  belongs_to :player
+  belongs_to :ptag
+end