Merge branch '56-remove-nativescript-from-ci' into 'master'

Resolve "remove nativescript from CI"

Closes #56

See merge request bloodyhealth/drip!13

.gitlab-ci.yml

-image: jfr3000/docker-nativescript
+image: node:8
 
 # This folder is cached between builds
 # http://docs.gitlab.com/ce/ci/yaml/README.html#cache