Add index to survey item responses on school and academic year.

db/migrate/20220614211616_add_school_and_year_index_to_survey_item_responses.rb

@@ -0,0 +1,5 @@
+class AddSchoolAndYearIndexToSurveyItemResponses < ActiveRecord::Migration[7.0]
+  def change
+    add_index :survey_item_responses, %i[school_id academic_year_id]
+  end
+end