fix plan stage issue and some spec failures

lib/gitlab/cycle_analytics/base_stage.rb

@@ -15,7 +15,9 @@ module Gitlab
       end
       def event
-        @event ||= Gitlab::CycleAnalytics::Event[stage].new(fetcher: @fetcher, options: @options, stage: stage)
+        @event ||= Gitlab::CycleAnalytics::Event[stage].new(fetcher: @fetcher,
+                                                            options: @options,
+                                                            stage: stage)
       end
       def events

lib/gitlab/cycle_analytics/metrics_fetcher.rb

@@ -47,7 +47,11 @@ module Gitlab
       end
       def order
-        @stage.event.order || @stage.start_time_attrs.is_a?(Array) ? @stage.start_time_attrs.first : @stage.start_time_attrs
+        @stage.event.order || default_order
+      end
+
+      def default_order
+        @stage.start_time_attrs.is_a?(Array) ? @stage.start_time_attrs.first : @stage.start_time_attrs
       end
       # Join table with a row for every <issue,merge_request> pair (where the merge request

lib/gitlab/cycle_analytics/plan_stage.rb

@@ -10,7 +10,7 @@ module Gitlab
       end
       def stage
-        :code
+        :plan
       end
       def description