Imports
- github.com/jinzhu/gorm
- github.com/gin-gonic/gin
- github.com/si9ma/KillOJ-common/utils
- github.com/jinzhu/gorm/dialects/mysql
- github.com/si9ma/KillOJ-backend/kerror
- github.com/si9ma/KillOJ-common/log
- github.com/si9ma/KillOJ-common/model
- github.com/smacker/opentracing-gorm
- go.uber.org/zap