implemented items method for merchant to work correctly
commented out invoice repo references in merchant for now until inv repo code is working
setup transaction and its test to have a working invoice class once inv repo code is working
wrote invoice item method for item class and its test
Merge branch 'master' into class_methods_tied_to_reps
wrote methods on item merchant and transaction to reference repos, still need invoicerepo and invitemrepo to work first
added metaprogramming code to implement find_by methods on invoice and invoice item repos
fixed attrs in metaprogramming blocks for inv and invitemrepo, uncommented already working code from item, merchant, and transaction classes