Checking in changes prior to tagging of version 0.07.

Changelog diff is:

diff --git a/Changes b/Changes
index 96936fe..457cee3 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,9 @@ Revision history for Perl extension DBIx::Schema::DSL

 {{$NEXT}}

+0.07 2013-07-29T03:20:58Z
+    - add DSL default_not_null (tokubass)
+
 0.06 2013-07-11T04:10:06Z
     - fix bug of `default_unsigned`
     - Switch to Minilla.