workspace    工作区 
index/stage  git add  存入stage/index暂存区
repository   git commit 存入repository本地仓库
remote       git push 存入remote远程仓库

remote  [fetch/clone]  repository [checkout] workspace
remote  [pull] workspace
workspace  [add] index [commit] repository [push] remote


git操作流程图 
https://gitee.com/dyyx/hellocode/raw/master/web/images/git.png