Update 2017-08-08-rest-api-testing.md
Update 2017-08-08-rest-api-testing.md

Add its header.
kyungmi/ridi.github.io,kyungmi/ridi.github.io,ridibooks/ridibooks.github.io,ridibooks/ridibooks.github.io,ridibooks/ridibooks.github.io,kyungmi/ridi.github.io