fix: change user_id index to user roles table to compound index

Author: tamassoltesz

CHANGELOG.md

@@ -15,7 +15,7 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 ### Migration
 
 ```sql
-CREATE INDEX IF NOT EXISTS user_roles_user_id_index ON user_roles (user_id);
+CREATE INDEX IF NOT EXISTS user_roles_app_id_tenant_id_user_id_index ON user_roles (app_id, tenant_id, user_id);
 ```
 ## [8.1.0]
 

src/main/java/io/supertokens/storage/postgresql/queries/UserRolesQueries.java

@@ -117,8 +117,8 @@ public static String getQueryToCreateUserRolesRoleIndex(Start start) {
     }
 
     public static String getQueryToCreateUserIdIndexForUserRolesTable(Start start) {
-        return "CREATE INDEX IF NOT EXISTS user_roles_user_id_index ON " + getConfig(start).getUserRolesTable() +
-                "(user_id);";
+        return "CREATE INDEX IF NOT EXISTS user_roles_app_id_tenant_id_user_id_index ON " + getConfig(start).getUserRolesTable() +
+                "(app_id, tenant_id, user_id);";
     }
 
     public static boolean createNewRoleOrDoNothingIfExists_Transaction(Start start, Connection con,