Keep all entropy definitions together in the concern

app/models/collection.rb

@@ -8,7 +8,6 @@ class Collection < ApplicationRecord
   has_many :tags, -> { distinct }, through: :cards
   has_many :events
   has_many :webhooks, dependent: :destroy
-  has_one :entropy, as: :container, dependent: :destroy
 
   scope :alphabetically, -> { order("lower(name)") }
   scope :ordered_by_recently_accessed, -> { merge(Access.ordered_by_recently_accessed) }

app/models/collection/entropic.rb

@@ -3,6 +3,7 @@ module Collection::Entropic
 
   included do
     delegate :auto_postpone_period, to: :entropy
+    has_one :entropy, as: :container, dependent: :destroy
   end
 
   def entropy