Update: n-Makefile from v14 -> v15 (#46)

n.Makefile

@@ -14,6 +14,8 @@ endif
 # Enforce repo ownership
 ifeq ("$(wildcard ft.yml)","")
 $(error 'Projects making use of n-makefile *must* define an ft.yml file containing the repo owner's details (see any next- repo for required structure)')
+$(error 'If you are creating a project not to be maintained by the next team please feel free to copy what you need from our build tools but don't add an ft.yml.')
+$(error 'Integrating with our tooling may result in unwanted effects e.g. nightly builds, slack alerts, emails etc')
 endif
 
 # ./node_modules/.bin on the PATH
@@ -28,7 +30,7 @@ NPM_INSTALL = npm prune --production=false && npm install
 BOWER_INSTALL = bower prune && bower install --config.registry.search=http://registry.origami.ft.com --config.registry.search=https://bower.herokuapp.com
 JSON_GET_VALUE = grep $1 | head -n 1 | sed 's/[," ]//g' | cut -d : -f 2
 IS_GIT_IGNORED = grep -q $(if $1, $1, $@) .gitignore
-VERSION = v14
+VERSION = v15
 APP_NAME = $(shell cat package.json 2>/dev/null | $(call JSON_GET_VALUE,name))
 DONE = echo ✓ $@ done
 CONFIG_VARS = curl -fsL https://ft-next-config-vars.herokuapp.com/$1/$(call APP_NAME)$(if $2,.$2,) -H "Authorization: `heroku config:get APIKEY --app ft-next-config-vars`"