Add task to migrate pull request data for builds

Rakefile

@@ -33,3 +33,6 @@ task 'travis-api.gemspec' do
 end
 
 task default: 'travis-api.gemspec'
+
+tasks_path = File.expand_path('../lib/tasks/*.rake', __FILE__)
+Dir.glob(tasks_path).each { |r| import r }

lib/tasks/build_update_pull_request_data.rake

@@ -0,0 +1,21 @@
+namespace :build do
+  namespace :migrate do
+    task :pull_request_data do
+      require 'travis'
+      Travis::Database.connect
+
+      Build.pull_requests.includes(:request).find_in_batches do |builds|
+        Build.transaction do
+          builds.each do |build|
+            attrs = {
+              :pull_request_number => build.request.pull_request_number,
+              :pull_request_title  => build.request.pull_request_title
+            }
+
+            Build.where(id: build.id).update_all(attrs)
+          end
+        end
+      end
+    end
+  end
+end