add cobar rule doc
add cobar rule doc

sforce100/cobar,elijah513/cobar,yidaimi/cobar,sawyer2011/cobar,xiaomizhg/cobar,fengshao0907/cobar,mlc0202/cobar,ys305751572/cobar,czd327917086/cobar,yidaimi/cobar,karlchan-cn/cobar,treejames/cobar,E312232595/cobar,yuzhu712/cobar,zhujzhuo/cobar,simplechen/cobar,sawyer2011/cobar,liuxinglanyue/cobar,fjlinhua/cobar,fengshao0907/cobar,karlchan-cn/cobar,logcos/cobar,logcos/cobar,xujianhai/cobar,elijah513/cobar,elijah513/cobar-1,ys305751572/cobar,E312232595/cobar,yuzhu712/cobar,mlc0202/cobar,elijah513/cobar-1,simplechen/cobar,logcos/cobar,xujianhai/cobar,yuzhu712/cobar,lindzh/cobar,yidaimi/cobar,elijah513/cobar,xujianhai/cobar,lindzh/cobar,karlchan-cn/cobar,treejames/cobar,simplechen/cobar,liuxinglanyue/cobar,xiaomizhg/cobar,czd327917086/cobar,treejames/cobar,elijah513/cobar-1,sforce100/cobar,sawyer2011/cobar,sforce100/cobar,mlc0202/cobar,czd327917086/cobar,fjlinhua/cobar,lindzh/cobar,E312232595/cobar,zhujzhuo/cobar,liuxinglanyue/cobar,ys305751572/cobar,zhujzhuo/cobar,fjlinhua/cobar,fengshao0907/cobar,xiaomizhg/cobar