forbid buy when event tickets quantity is 0 or not enough quantity
Merge pull request #506 from richard-ma/master

更新friendly_id的repo地址 fix #505
using friendly-id new api
Merge branch 'pr504'

Conflicts:
	app/controllers/event_orders_controller.rb
	app/models/event_order.rb
	app/views/events/show.html.slim
	db/schema.rb
	spec/features/event_orders_spec.rb
	spec/models/event_order_spec.rb
Merge pull request #507 from jasl/fix-friendly-id

更新friendly-id的调用
Fix spec failures
fix bugged spec
merge fix spec
Merge pull request #509 from jasl/forbid_participant_when_no_ticket

修改了spec
update gems and move executable to bin from script
fix guard and foreman rails log output
Merge pull request #510 from jasl/more-rails4

更新了gems
Use ruby to check whether phantomjs exists.

`which` does not exists in Windows, and `which x` may returns nil
instead of string.

Refs #515
Suppress Thin logging in rspec.
database_cleaner 1.1.1 has a bug when using sqlite
Merge pull request #516 from doitian/spec_helper_refactoring

Refactor spec_helper
Merge pull request #517 from jasl/back-database-cleaner

修复使用sqlite3时database_cleaner错误的使用pg_adapter而异常