Finished phase005

app/models/fuel_entry.rb

@@ -7,6 +7,7 @@ class FuelEntry < ApplicationRecord
   validates :price_paid, presence: true, numericality: { greater_than: 0 }
   validates :date, presence: true
   validate :date_cannot_be_in_the_future
+  validate :odometer_cannot_be_less_than_vehicle_current_odometer
 
   private
 
@@ -15,4 +16,11 @@ class FuelEntry < ApplicationRecord
 
     errors.add(:date, "can't be in the future")
   end
+
+  def odometer_cannot_be_less_than_vehicle_current_odometer
+    return if vehicle.blank? || odometer.blank?
+    return if odometer >= vehicle.current_odometer
+
+    errors.add(:odometer, "cannot be less than the vehicle's current odometer")
+  end
 end