Upgrade angular version
add info page
Change scrollbar style
Add practise page
Merge branch 'feature/add_link_result_contest' of https://github.com/npphuongthanh/easylearncode into npphuongthanh-feature/add_link_result_contest

Conflicts:
	application/handlers.py
Merge branch 'feature/add_info_page' of https://github.com/nguyenngochan/easylearncode into nguyenngochan-feature/add_info_page

Conflicts:
	application/handlers.py
	application/static/js/main.js