创建experiments app
完成experiment app的LessonCategory model 和Lesson model
删除无用代码
修改setting.py中INSTALLED_APP处添加experiments的代码缩进问题
Merge branch 'develop' into feature/experiment_model_design

Conflicts:
	OEMS/settings.py
修复命名风格
Merge branch 'develop' into feature/experiment_model_design
添加experiment数据库迁移
Merge branch 'develop' into feature/experiment_model_design
修改experiment目录下models.py中的代码缩进问题
experiment的建模
experimernt建模
experimernt建模修改
删除无用迁移
Merge branch 'develop' into feature/experiment_model_design
修复migration迁移
修改experiment/models.py中Lesson name字段的null=False
Merge branch 'feature/experiment_model_design' of github.com:qdulab/OEMS into feature/experiment_model_design
添加templates/experiment文件夹
merge