up: add uniqueness on voting based on resource id

lib/rating/models/rating/rating.rb

@@ -10,6 +10,11 @@ module Rating
     validates :average, :estimate, :resource, :sum, :total, presence: true
     validates :average, :estimate, :sum, :total, numericality: true
 
+    validates :resource_id, uniqueness: {
+      case_sensitive: false,
+      scope:          %i[resource_type scopeable_id scopeable_type]
+    }
+
     class << self
       def averager_data(resource, scopeable)
         total_count    = how_many_resource_received_votes_sql?(distinct: false, scopeable: scopeable)

spec/factories/rating/rating.rb

@@ -7,6 +7,6 @@ FactoryBot.define do
     sum      100
     total    1
 
-    resource { create :article }
+    association :resource, factory: :article, strategy: :build
   end
 end

spec/models/rating_spec.rb

@@ -15,4 +15,10 @@ RSpec.describe Rating::Rating do
   it { is_expected.to validate_presence_of :resource }
   it { is_expected.to validate_presence_of :sum }
   it { is_expected.to validate_presence_of :total }
+
+  it do
+    expect(object).to validate_uniqueness_of(:resource_id)
+      .scoped_to(%i[resource_type scopeable_id scopeable_type])
+      .case_insensitive
+  end
 end