1. Copy src/models/skel.h to src/models/your_model_name.h

2. replace all occurence of MODEL in src/models/your_model_name.h by
   your_model_name
   e.g. sed -r 's/MODEL/your_model_name/g' -i src/models/your_model_name.h

3. Edit the file src/models/your_model_name.h, following instructions in
   comments

4. Edit src/dispatcher.h you must 
    - add your model/your_model_name.h in includes
    - add 3 line (and one blank line) in the dispatcher model, search bernoulli
      and poisson to understand

5. Edit src/Makevars, add -Wall to PKG_CPPFLAGS

6. Compile your code. As your modification are in .h files, you must touch the
   file src/dispatcher.cc at each recompilation to force recompilation.

   cd ..
   touch blockmodels/src/dispatcher.cc
   R CMD INSTALL blockmodels

   If you want to submit your model, the compilation must be done WITHOUT any
   warnings.

7. Write R RefClass for the model, inheriting from scalar_model,
   scalar_model_with_covarariates, multivariate_model, ... or model directly if you
   want.

8. Write R documentation file and tests.

   * write code in orig/code/your_model_name.R. Use variables as others.

   * write man with macro in orig/man/your_model_name.Rd. Use variables as
     others.

   * run ./gen_mans_and_tests

9. Set export of you model in NAMESPACE.