install nodejs/npm on workers

for Scala.js. requested by @sjrd at scala/community-build#276

Author: SethTisue

doc/staging.md

@@ -41,6 +41,7 @@ knife cookbook site install partial_search
 knife cookbook site install ssh_known_hosts
 knife cookbook site install git_user
 knife cookbook site install chef-vault
+knife cookbook site install nodejs
 ```
 
 ### Current cookbooks
@@ -60,6 +61,7 @@ knife cookbook site install chef-vault
  - git_user            ==  0.3.1
  - java                ==  1.39.0
  - logrotate           ==  1.9.1
+ - nodejs              ==  2.4.4
  - packagecloud        ==  0.0.17
  - partial_search      ==  1.0.8
  - runit               ==  1.6.0

metadata.rb

@@ -32,4 +32,7 @@
 depends 'chef-sbt'
 depends 'sbt-extras'
 
-depends 'runit', '~> 1.5'
+depends 'runit', '~> 1.5'
+
+depends 'nodejs'
+

recipes/_worker-init-debian.rb

@@ -9,6 +9,8 @@
 
 include_recipe "apt" # do apt-get update
 
+include_recipe "nodejs"  # for Scala.js
+
 include_recipe "scala-jenkins-infra::_java_packages"
 
 # NOTE: MUST BE LAST -- it selects the chef-configured jdk (the above packages install openjdk 7 & 8, but we want something else)