fix review request constraint

db/migrate/20230504002009_change_review_request_answered_to_not_nil.rb

@@ -0,0 +1,7 @@
+class ChangeReviewRequestAnsweredToNotNil < ActiveRecord::Migration[7.0]
+  def change
+    ReviewRequest.where(answered: nil).update_all(answered: false)
+
+    change_column_null :review_requests, :answered, false
+  end
+end