Update db/migrate/20240905024953_move_solved_topic_custom_field_to_discourse_solved_solutions.rb

Co-authored-by: Bianca Nenciu <nbianca@users.noreply.github.com>

Author: Lhcfl

db/migrate/20240905024953_move_solved_topic_custom_field_to_discourse_solved_solutions.rb

@@ -7,7 +7,7 @@ def up
       t.integer :topic_id, null: false
       t.integer :answer_post_id, null: false
       t.integer :accepter_user_id
-      t.integer :topic_timer_id, null: true
+      t.integer :topic_timer_id
       t.timestamps
     end