added inspect method to mapping

lib/gom/object/mapping.rb

@@ -35,6 +35,12 @@ def clear!
     @map.clear
   end
 
+  def inspect
+    output = ""
+    @map.each{ |object, id| output += object.inspect + " => " + id.to_s + "\n" }
+    output
+  end
+
   def self.singleton
     @mapping ||= self.new
   end

spec/lib/gom/object/mapping_spec.rb

@@ -89,6 +89,15 @@
 
     end
 
+    describe "inspect" do
+
+      it "should return a string with all the mappings" do
+        output = @mapping.inspect
+        output.should =~ /#<Object:.*> => test_storage:object_1\n/
+      end
+
+    end
+
   end
 
   describe "class method" do