Small change to release instructions

doc/internal/how_to_release.txt

@@ -22,7 +22,7 @@ Edit ``doc/index.txt`` to contain a link to what will be the download URL::
 
 Tag the release. The syntax is something like the following::
 
-    hg tag
+    hg tag Theano-0.X
 
 Now, package the release and move it to the static theano directory::