suggested mapping for NCBI databases

[bradfordcondon]

I'm creating a Tripal module that imports NCBI XML and creates chado records, as well as linked records.

I think it would be neat to have a recommended, agreed upon mapping of NCBI data into chado. This could go into the documentation/wiki. ie bioproject -> project biosample -> biomaterial assembly -> analysis of type X . (note that some @laceysanderson might argue this should actualy be a project since its multiple analyses?)