diff --git a/sql/branch.sql b/sql/branch.sql
new file mode 100644
index 0000000000..eddce05907
--- /dev/null
+++ b/sql/branch.sql
@@ -0,0 +1,4 @@
+ALTER TABLE emails ADD COLUMN participant_id bigint DEFAULT NULL
+	REFERENCES participants(id) ON UPDATE RESTRICT ON DELETE RESTRICT;
+
+ALTER TABLE emails ADD UNIQUE (participant_id, address);
\ No newline at end of file