Add DomainBlock#accounts has_many

app/models/domain_block.rb

@@ -7,6 +7,9 @@ class DomainBlock < ApplicationRecord
 
   validates :domain, presence: true, uniqueness: true
 
+  has_many :accounts, foreign_key: :domain, primary_key: :domain
+  delegate :count, to: :accounts, prefix: true
+
   def self.blocked?(domain)
     where(domain: domain, severity: :suspend).exists?
   end

app/views/admin/domain_blocks/show.html.haml

@@ -9,7 +9,7 @@
     label: t(".retroactive.#{@domain_block.severity}"),
     hint: t(:affected_accounts,
       scope: [:admin, :domain_blocks, :show],
-      count: Account.where(domain: @domain_block.domain).count)
+      count: @domain_block.accounts_count)
 
   .actions
     = f.button :button, t('.undo'), type: :submit