Support plugins being a list of directories to scan.

lib/jekyll/site.rb

@@ -18,7 +18,13 @@ module Jekyll
       self.safe            = config['safe']
       self.source          = File.expand_path(config['source'])
       self.dest            = File.expand_path(config['destination'])
-      self.plugins         = File.expand_path(config['plugins'])
+      self.plugins         = if config['plugins'].respond_to?('each')
+                               # If plugins is an array, process it.
+                               config['plugins'].each { |directory| File.expand_path(directory) }
+                             else
+                               # Otherwise process a single entry as an array.
+                               [File.expand_path(config['plugins'])]
+                             end
       self.lsi             = config['lsi']
       self.pygments        = config['pygments']
       self.permalink_style = config['permalink'].to_sym
@@ -72,10 +78,12 @@ module Jekyll
       # If safe mode is off, load in any Ruby files under the plugins
       # directory.
       unless self.safe
-        Dir[File.join(self.plugins, "**/*.rb")].each do |f|
+        self.plugins.each do |plugins|
+            Dir[File.join(plugins, "**/*.rb")].each do |f|
               require f
             end
         end
+      end
 
       self.converters = Jekyll::Converter.subclasses.select do |c|
         !self.safe || c.safe