Index: sql/iknow.dbml
===================================================================
--- sql/iknow.dbml	(revision ea405569ef29f56fbfc4d77708b6b3faf9286097)
+++ sql/iknow.dbml	(revision c42181c14003c8cccadbc27f9c9ec5991b0ea286)
@@ -150,5 +150,4 @@
 Table project.payment {
   id integer [pk, increment]
-  user_id integer [not null]
   enrollment_id integer [not null]
   amount integer [not null]
@@ -188,5 +187,4 @@
 Ref: project.contact.user_id - project.users.id                      // has_contact (1:1)
 Ref: project.token.user_id > project.users.id                        // has_token
-Ref: project.payment.user_id > project.users.id                      // pays
 Ref: project.payment.enrollment_id > project.enrolled_semesters.id   // for_enrollment
 Ref: project.enrolled_semesters.user_id > project.users.id           // submits