Send emails to current budget authors in rake tasks

We were using `Budget.last`, but the last budget might not be published
yet.

I must admit I don't know whether these tasks are useful, but I'm not
removing them because I'm not sure that won't harm any CONSUL
installations.

lib/tasks/budgets.rake

@@ -2,12 +2,12 @@ namespace :budgets do
   namespace :email do
     desc "Sends emails to authors of selected investments"
     task selected: :environment do
-      Budget.last.email_selected
+      Budget.current.email_selected
     end
 
     desc "Sends emails to authors of unselected investments"
     task unselected: :environment do
-      Budget.last.email_unselected
+      Budget.current.email_unselected
     end
   end
 end

spec/lib/tasks/budgets_spec.rb

@@ -0,0 +1,31 @@
+require "rails_helper"
+
+describe "budget tasks" do
+  describe "rake budgets:email:selected" do
+    before { Rake::Task["budgets:email:selected"].reenable }
+
+    it "sends emails to users from the current budget and not the last budget created" do
+      create(:budget_investment, :selected, author: create(:user, email: "selectme@consul.dev"))
+      create(:budget, :drafting)
+
+      Rake.application.invoke_task("budgets:email:selected")
+
+      expect(ActionMailer::Base.deliveries.count).to eq 1
+      expect(ActionMailer::Base.deliveries.last.to).to eq ["selectme@consul.dev"]
+    end
+  end
+
+  describe "rake budgets:email:unselected" do
+    before { Rake::Task["budgets:email:unselected"].reenable }
+
+    it "sends emails to users from the current budget and not the last budget created" do
+      create(:budget_investment, author: create(:user, email: "ignorme@consul.dev"))
+      create(:budget, :drafting)
+
+      Rake.application.invoke_task("budgets:email:unselected")
+
+      expect(ActionMailer::Base.deliveries.count).to eq 1
+      expect(ActionMailer::Base.deliveries.last.to).to eq ["ignorme@consul.dev"]
+    end
+  end
+end