Merge pull request #39 from COSI236TA/wenbin

Wenbin
modify rule_controller such that eception would not be raised
tiny move on rule engine
remove duplicate css and js
Merge branch 'master' of https://github.com/COSI236TA/Trade_Assistant
very first implementation
change database schema
improved RuleEngine. need to see its robustness
fix stupid bug introdued by stupid validation
initialize rule history every time the server starts
tiny modification on schema
RuleEngine basically done
change last_triggered to trigger? and change the return value. now it returns the datetime.
RuleHistory should tolerate multiple history entries but need more sophiscated algorithm to avoid duplicate entries on same event
basic scroll functionality succeed
basically done rule input page