implement delete session

sqlite/query.sql

@@ -226,6 +226,10 @@ WHERE id = ?;
 INSERT INTO sessions (id, user_id, expires_at)
 VALUES (?, ?, ?);
 
+-- name: DeleteSession :exec
+DELETE FROM sessions
+WHERE id = ?;
+
 -- name: RevokeClientApproval :exec
 DELETE  FROM client_approvals
 WHERE user_id = ? AND client_id = ?;