Merge pull request #139 from caok/master

modify something in rank and instruction
Update README.md
Update README.md
Update README.md
Create dev_diary
Update dev_diary
Update dev_diary
added event fold for organize event related issue
Update first_online.markdown
Update first_online.markdown
Update first_online.markdown
Update first_online.markdown
Update first_online.markdown
Merge pull request #143 from caok/master

modify the avatar
give a tips when request finish project not available
Merge pull request #144 from williamherry/tips-for-disabled-button

give a tips when request finish project not available
Fixed #141
ranking
Merge pull request #149 from williamherry/ranking

ranking 得分排行, 现在用户名的utl是'#'
add field to store github nickname
handle old data: login again will add nickname