fix teacher form

app/views/admin/education/program/teachers/_form.html.erb

@@ -7,7 +7,7 @@
         </div>
         <div class="card-body">
           <% teacher_ids = @program.teachers.where.not(id: teacher.id).pluck(:person_id) %>
-          <%= f.association :person, collection: current_university.people.teachers.where(id: teacher_ids).ordered %>
+          <%= f.association :person, collection: current_university.people.teachers.where.not(id: teacher_ids).ordered %>
           <%= f.input :description, input_html: { rows: 5 } %>
         </div>
       </div>