Corrected with rubocop cop 'Rails/Validation'.

.rubocop.yml

@@ -266,8 +266,6 @@ Style/InfiniteLoop:
   Enabled: false
 Lint/AmbiguousRegexpLiteral:
   Enabled: false
-Rails/Validation:
-  Enabled: false
 Lint/Eval:
   Enabled: false
 Style/ModuleFunction:

app/models/authorization.rb

@@ -5,8 +5,9 @@ class Authorization < ApplicationModel
   after_create  :delete_user_cache
   after_update  :delete_user_cache
   after_destroy :delete_user_cache
-  validates_presence_of   :user_id, :uid, :provider
-  validates_uniqueness_of :uid,     scope: :provider
+  validates     :user_id,  presence: true
+  validates     :uid,      presence: true, uniqueness: { scope: :provider }
+  validates     :provider, presence: true
 
   def self.find_from_hash(hash)
     auth = Authorization.where( provider: hash['provider'], uid: hash['uid'] ).first