Implement `mkdir' task action

lib/producer/core/actions/mkdir.rb

@@ -0,0 +1,15 @@
+module Producer
+  module Core
+    module Actions
+      class Mkdir < Action
+        def apply
+          fs.mkdir path
+        end
+
+        def path
+          arguments.first
+        end
+      end
+    end
+  end
+end

lib/producer/core/remote/fs.rb

@@ -26,6 +26,10 @@ module Producer
           false
         end
 
+        def mkdir(path)
+          sftp.mkdir! path
+        end
+
         def file_write(path, content)
           sftp.file.open path, 'w' do |f|
             f.write content

lib/producer/core/task/dsl.rb

@@ -13,6 +13,7 @@ module Producer
         define_action :echo,  Actions::Echo
         define_action :sh,    Actions::ShellCommand
 
+        define_action :mkdir,       Actions::Mkdir
         define_action :file_write,  Actions::FileWriter
 
         attr_reader :env, :block, :actions