Add time_format option to simple column (closes lunich#3)

lib/table_for/simple_column.rb

@@ -1,7 +1,11 @@
 module TableHelper
   class SimpleColumn < Column # :nodoc:
     def content_for(record)
-      record.send(@attr).to_s
+      called_record = record.send(@attr)
+      if @options[:time_format] and called_record.is_a? Time
+        called_record = called_record.strftime(@options[:time_format])
+      end
+      called_record.to_s
     end
   end
 end

spec/table_for/simple_column_spec.rb

@@ -6,7 +6,7 @@
   # TableHelper::SimpleColumn
   let(:klass) { TableHelper::SimpleColumn }
   # user (stubbed data)
-  let(:user) { mock(:id => 12) }
+  let(:user) { mock(:id => 12, :created_at => Time.gm(2011, "feb", 24, 14, 23, 1)) }
   # Instance methods
   describe "an instance" do
     it_should_behave_like "Column class instance"
@@ -26,5 +26,12 @@
       col = build_column(klass, :id)
       col.content_for(user).should == user.id.to_s
     end
+
+    describe "format" do
+      it ":time_format should be displayed correctly" do
+        col = build_column(klass, :created_at, :time_format => '%Y-%m')
+        col.content_for(user).should == "2011-02"
+      end
+    end
   end
 end