adding readme

Specifications/Originals/readme.md

+
+
+##### Constellation diagrams
+
+The diagrams show conceptual table names, which mirror the SQL database schema. An identity
+has one record in each table unless noted as repeatable.
+
+constellation_linked.gv.svg is an over view showing how two related records are linked via identity
+relation. Each record is independent. The only link between records is the identity relation which had one
+record for each side of the relationship. For reasons of clarity, the two identity constellations are not
+shown in full detail.
+
+identity_constellation_repeats.gv.svg is a detailed view of a single identity constellation with repeatable
+recorda noted.
+
+identity_constellation.gv.svg is an earlier, simplified view of the data. 
+