diff --git a/config/sql/users.sql b/config/sql/users.sql
index dde3b924f..e46cd744b 100644
--- a/config/sql/users.sql
+++ b/config/sql/users.sql
@@ -7,7 +7,8 @@ CREATE TABLE public.users
     id text COLLATE pg_catalog."default" NOT NULL,
     updated timestamp with time zone,
     notifications integer,
-    subscriptions text[] COLLATE pg_catalog."default"
+    subscriptions text[] COLLATE pg_catalog."default",
+    CONSTRAINT users_id_key UNIQUE (id)
 )
 WITH (
     OIDS = FALSE