Add rake task to set the original_heading_id value

By default we want this attribute to be the current heading id for existing investments. If there have been reclassifications, this field should be updated accordingly.

lib/tasks/budgets.rake

@@ -23,4 +23,14 @@ namespace :budgets do
 
   end
 
+  desc "Update investments original_heading_id with current heading_id"
+  task set_original_heading_id: :environment do
+    puts "Starting"
+    Budget::Investment.find_each do |investment|
+      investment.update_column(:original_heading_id, investment.heading_id)
+      print "."
+    end
+    puts "Finished"
+  end
+
 end

spec/lib/tasks/budgets_spec.rb

@@ -0,0 +1,22 @@
+require "rails_helper"
+
+describe Budget do
+
+  let(:run_rake_task) do
+    Rake.application.invoke_task("budgets:set_original_heading_id")
+  end
+
+  it "sets attribute original_heading_id for existing investments" do
+    heading = create(:budget_heading)
+    investment = create(:budget_investment, heading: heading)
+    investment.update(original_heading_id: nil)
+
+    expect(investment.original_heading_id).to equal(nil)
+
+    run_rake_task
+    investment.reload
+
+    expect(investment.original_heading_id).to equal(heading.id)
+  end
+
+end