-i (Input Option) Instruction

[sungbin]

When you push option: -i <input>

-i https://github.com/apache/zookeeper -o "output/path"

-i https://github.com/apache/zookeeper -r "reference/file/path" -o "output/path"

if target project does not have issue pages in GitHub, you should use -r option

you can get information about -r option from here