There is no really quick fix for adding an item back to a context menu that I know of - I know a couple, but it's a very involved procedure and a little risky (involves RegEdit). However, if I can be bold enough to make a suggestion, try
7-zip. It adds a context menu for adding files to archives. It's a bit more complicated, in that it has more options, but you probably will only ever use this one:
Or the one below, which is even faster ("Add to 'filename.zip'")