Internal state persistence (#27)

Allow us to generate year over year reports without having to rerun everything from the beginning.

Co-authored-by: Natercio Moniz <[email protected]>

internal/generate.go

@@ -1,3 +1,3 @@
 package internal
 
-//go:generate go tool mockgen -destination=mocks/mocks_gen.go -package=mocks -typed . RecordReader,Record,ReportWriter
+//go:generate go tool mockgen -destination=mocks/mocks_gen.go -package=mocks -typed . RecordReader,Record,ReportWriter,RecordEncoder,RecordDecoder,RecordSerializer