[#4604] Clear and recalculate the #cost on Rate#save

app/models/rate.rb

@@ -11,6 +11,7 @@ class Rate < ActiveRecord::Base
   validates_numericality_of :amount
   
   before_save :unlocked?
+  after_save :update_time_entry_cost_cache
   before_destroy :unlocked?
   
   named_scope :history_for_user, lambda { |user, order|
@@ -36,6 +37,10 @@ class Rate < ActiveRecord::Base
   def specific?
     return !self.default?
   end
+
+  def update_time_entry_cost_cache
+    TimeEntry.update_cost_cache(user, project)
+  end
   
   # API to find the Rate for a +user+ on a +project+ at a +date+
   def self.for(user, project = nil, date = Date.today.to_s)