(quality) disable Rails/RedundantPresenceValidationOnBelongsTo

This setting was disabled in config/application.rb:
`config.active_record.belongs_to_required_by_default = false`,
so we must configure the linter accordingly.

Also: linting some little bit of code

.rubocop.yml

@@ -36,3 +36,5 @@ Style/FormatString:
   EnforcedStyle: sprintf
 Style/FormatStringToken:
   EnforcedStyle: template
+Rails/RedundantPresenceValidationOnBelongsTo:
+  Enabled: false

app/controllers/api/wallet_controller.rb

@@ -18,7 +18,7 @@ class API::WalletController < API::ApiController
   end
 
   def credit
-    return head 422 unless Setting.get('wallet_module')
+    return head :unprocessable_entity unless Setting.get('wallet_module')
 
     @wallet = Wallet.find(credit_params[:id])
     authorize @wallet
@@ -28,7 +28,7 @@ class API::WalletController < API::ApiController
       service.create_avoir(transaction, credit_params[:avoir_date], credit_params[:avoir_description]) if credit_params[:avoir]
       render :show
     else
-      head 422
+      head :unprocessable_entity
     end
   end
 

app/models/wallet.rb

@@ -11,6 +11,8 @@ class Wallet < ApplicationRecord
 
   validates :invoicing_profile, presence: true
 
+  delegate :user, to: :invoicing_profile
+
   def credit(amount)
     if amount.is_a?(Numeric) && amount >= 0
       self.amount += amount
@@ -26,8 +28,4 @@ class Wallet < ApplicationRecord
     end
     false
   end
-
-  def user
-    invoicing_profile.user
-  end
 end

app/models/wallet_transaction.rb

@@ -14,6 +14,7 @@ class WalletTransaction < ApplicationRecord
   has_one :invoice_item, as: :object, dependent: :destroy
 
   validates :transaction_type, inclusion: { in: %w[credit debit] }
+  validates :invoicing_profile, :wallet, presence: true
 
   delegate :user, to: :invoicing_profile