Limit users to 50 lists, remove pagination from lists API (#5933)

app/models/list.rb

@@ -13,6 +13,8 @@
 class List < ApplicationRecord
   include Paginable
 
+  PER_ACCOUNT_LIMIT = 50
+
   belongs_to :account
 
   has_many :list_accounts, inverse_of: :list, dependent: :destroy
@@ -20,6 +22,10 @@ class List < ApplicationRecord
 
   validates :title, presence: true
 
+  validates_each :account_id, on: :create do |record, _attr, value|
+    record.errors.add(:base, I18n.t('lists.errors.limit')) if List.where(account_id: value).count >= PER_ACCOUNT_LIMIT
+  end
+
   before_destroy :clean_feed_manager
 
   private