New plugin env.rb to make env vars available in templates

.travis.yml

@@ -3,5 +3,9 @@ rvm:
   - "2.0.0"
 sudo: false
 cache: bundler
+env:
+  # http://docs.travis-ci.com/user/environment-variables/#Global-Variables
+  global:
+    - BITCOINORG_BUILD_TYPE=deployment
 
 script: make travis

_plugins/env.rb

@@ -0,0 +1,20 @@
+# This file is licensed under the MIT License (MIT) available on
+# http://opensource.org/licenses/MIT.
+
+## env.rb takes select environmental variables and makes them available
+## to the site templates. Currently, only variables starting with
+## BITCOINORG_ are exported
+
+module Jekyll
+  class EnvGenerator < Generator
+    def generate(site)
+      ## If necessary, initialize env hash table
+      site.config["env"] = site.config["env"] ? site.config["env"] : {}
+
+      ## Load matching environmental variables in to array
+      ENV.keys.grep /^BITCOINORG_/ do |key|
+        site.config['env'].merge!({ key => ENV[key] })
+      end
+    end
+  end
+end