add stock resourse
add listing stocks page
add rake task. this can be executed by heroku scheduler
add exception handling in rule_engine and data_updater
add buttons to portfolio; add routes to portfolio
Merge pull request #46 from COSI236TA/integrate

Integrate
merge from master; conflict fixed
Merge pull request #47 from COSI236TA/wenbin

Wenbin
Fixed routes portfolio issue