fix ruby variables

lib/vool/assignment.rb

@@ -0,0 +1,19 @@
+module Vool
+
+  class Assignment < Statement
+    attr_reader :name , :value
+    def initialize(name , value )
+      @name , @value = name , value
+    end
+
+    def each(&block)
+      block.call(self)
+      @value.each(&block)
+    end
+
+    def to_s(depth = 0)
+      at_depth(depth , "#{@name} = #{@value}")
+    end
+
+  end
+end