In constraint programming, a regular constraint is a special global constraint very useful in scheduling, in particular for the easy modeling of rostering problems. This constraint enforces a sequence of variables to take a value defined by a deterministic finite automaton. In practice, when the user models the problem, regular constraints are programmed in the language of the solving engine, which is in most cases a proprietary language or a classic programming language. However, there exists several modeling languages and very different encoding patterns for the regular constraint, turning the modeling into a tedious task. In this paper, we present a simple GUI for modeling regular constraints that clearly increases the usability for end-users. The tool allows to easily draw finite automata, which are automatically translated to the corresponding code of the regular constraint for the target solving engine.