Added homework directory and demo.md
Create homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Update homework-group.md
Merge pull request #1 from ducs-personal/master

开源课程意见