rename Matching to OldMatching
add market, and follow convention 'btccny' in which seller's commodity is placed before buyer's commodity
rename variables in Market
add Matching::Order
no need for target in Matching::Order
add Matching::OrderBook
leave old market id untouched so I can focus on engine stuff
matching trade executor
add Matching::FIFOEngine
fix circular reference when calling market.to_json, and engine should be hidden from outside
add Job::Matching
delivery Pusher message in Executor
initialize market in Matching::Order
well, just chained everything up
validate orders before trade execution
enqueue matching job on order creation
make engine not to continue process previous orders by default
add rake performance task
refactor engine to accept options
refactor matching engine