Set up association and models

app/models/booth.rb

@@ -7,6 +7,7 @@ class Booth < ApplicationRecord
   attr_accessor :invite_responsible
 
   belongs_to :conference
+  belongs_to :booth_type
   has_many :booth_requests, dependent: :destroy
   has_many :users, through: :booth_requests
 

app/models/booth_type.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class BoothType < ApplicationRecord
+  belongs_to :program, touch: true
+  has_many :booths, dependent: :restrict_with_error
+
+  has_paper_trail meta:   { conference_id: :conference_id },
+                  ignore: %i[updated_at]
+
+  validates :title, presence: true
+
+  private
+
+  def conference_id
+    program.conference_id
+  end
+end

app/models/conference.rb

@@ -52,6 +52,7 @@ class Conference < ApplicationRecord
            through: :program,
            source:  :events
   has_many :event_types, through: :program
+  has_many :booth_types, through: :program
 
   has_many :surveys, as: :surveyable, dependent: :destroy do
     def for_registration

app/models/program.rb

@@ -9,6 +9,7 @@ class Program < ApplicationRecord
 
   has_many :cfps, dependent: :destroy
   has_many :event_types, dependent: :destroy
+  has_many :booth_types, dependent: :destroy
   has_many :tracks, dependent: :destroy
   has_many :difficulty_levels, dependent: :destroy
   has_many :schedules, dependent: :destroy