$ git push ssh://yourserver.com/~you/proj.git +master
-------------------------------------------------
+Note the addition of the `+` sign. Alternatively, you can use the
+`-f` flag to force the remote update, as in:
+
+-------------------------------------------------
+$ git push -f ssh://yourserver.com/~you/proj.git master
+-------------------------------------------------
+
Normally whenever a branch head in a public repository is modified, it
is modified to point to a descendant of the commit that it pointed to
before. By forcing a push in this situation, you break that convention.