Remove the duplicated configuration.
Add the audit logs for deposit and withdraw.
Merge branch 'master' into audit_log

Conflicts:
	db/schema.rb
Updated the annoate.
Move the audit related model to audit folder.
Move the audit reloated class to the right context.
After a long talk with Jan. We make a decison that.
1. Use Member.current instead of get current_user from controller.
2. So no need use Sweeper and use standard observer.
Add tests for the audit log related stuff.
Merge pull request #121 from peatio/audit_log

Add audit log to Peatio