Actually use submission series

app/controllers/submissions_controller.rb

@@ -95,8 +95,11 @@ def edit
       format.html do
         if @submission.course.nil?
           redirect_to activity_url(@submission.exercise, anchor: 'submission-card', edit_submission: @submission)
-        else
+        elsif @submission.series.nil?
+          Rails.logger.debug 'Redirecting to course_activity_url==========================================================='
           redirect_to course_activity_url(@submission.course, @submission.exercise, anchor: 'submission-card', edit_submission: @submission)
+        else
+          redirect_to course_series_activity_url(@submission.course, @submission.series, @submission.exercise, anchor: 'submission-card', edit_submission: @submission)
         end
       end
     end

app/models/submission.rb

@@ -147,17 +147,6 @@ def result=(result)
     File.binwrite(File.join(fs_path, RESULT_FILENAME), ActiveSupport::Gzip.compress(result.force_encoding('UTF-8')))
   end
 
-  def series
-    return nil if course.nil?
-
-    series = course.series
-    # we want to avoid accidentally linking a hidden series to a student
-    series = series.visible
-    # There could actually be multiple series with the same exercise and the same course
-    # But for now we just return the first one, as there is only one in most cases
-    series.joins(:series_memberships).find_by(series_memberships: { activity: exercise })
-  end
-
   def clean_messages(messages, levels)
     messages.select { |m| !m.is_a?(Hash) || !m.key?(:permission) || levels.include?(m[:permission]) }
   end