[erlang-questions] Access control framework and method for data versioning

[Schneider]

Dear list,

I am looking for an (Erlang based) access control framework for an 
application for processing medical records. The ideal framework would 
offer policy based access control in a distributed environment. A rule 
based access control system would be the next best option. Role based 
access and things like ACLs are not really good solutions.

For the same application, I need to implement versioning of data, i.e. 
data should not be changed after it is recorded but superseded by a new 
version offering a full history of the data. Data is stored in some 
NoSQL database system.
I would love to hear some suggestions on implementing versioning of data.

/Frans