Add Ricardo Lafuente to CONTRIBUTORS list
Add Ricardo Lafuente to CONTRIBUTORS list

Email is missing/unknown

okfn/datapackage-model-py,okfn/datapackage-model-py,okfn/datapackage-py,sirex/datapackage-py,okfn/datapackage-py,datapackages/datapackage-py,sirex/datapackage-py,datapackages/datapackage-py