add license (will confirm with past contributors by e-mail on sipb-www@)

diff --git a/index.mdwn b/index.mdwn
index 115f77943b2bfdf1fdd1a43826afcfef7854293b..cae14ed41e255bc91294931d4e122986de3fa0e5 100644 (file)
--- a/index.mdwn
+++ b/index.mdwn
@@ -53,3 +53,11 @@ SIPB is always open to new contributors.  You can join one of the projects above
 ----
 
 This wiki is powered by [ikiwiki](http://ikiwiki.info).
+
+Unless otherwise specified, all content on this wiki is released under a dual license of
+
+ * the Creative Commons Attribution-Share Alike license, and
+ * the GNU Free Documentation License, with no Invariant Sections, no
+   Front-Cover Texts, and no Back-Cover-Texts.
+
+This follows the [SIPB Documentation Licensing Recommendation](http://stuff.mit.edu/afs/sipb/admin/text/policy/documentation_licensing.txt).