In this paper, we show that the business rules knowledge representation paradigm, which is widely used in the industry, can be developped as a front-end modelling language for constraint programming. We present a general purpose rule-based modelling language, called Rules2CP, and describe its compilation to constraint programs over finite domains with reified and global constraints, using term rewriting and partial evaluation. We prove the confluence of these transformations and provide a complexity bound on the size of the generated programs. The expressiveness of Rules2CP is illustrated with a complete library for packing problems, called PKML, which, in addition to pure bin packing and bin design problems, can deal with common sense rules about weights, stability, as well as specific packing business rules which compile efficiently into constraints.