The first step is you need to have `gpg` installed.
The most part of these 2 hours were fighting with "MacPorts" and "HomeBrew" to install `gpg`. Why? because MacPort does not allow me to upgrade `libiconv` when I tried to install `gnupg`, and as a result, I uninstalled `MacPort` which had been served me for over 2 years. I chose `HomeBrew` as my new partner, when I downloaded it and installed `gnupg`, it still told me again for build error. WTF? What's the problem? When I was at a loss what to do, suddenly I saw that brew provided a funny function as 'brew doctor', I ran it, it told me to remove "GREP_COLOR='--color=always'" in my `.bashrc` file and told me that's the reason for CMake failed to work! Oh My god, that's the problem! The rest was easy to go.
`brew install gpgme` // to install gpg, you'd better to install gpgme
`gpg --gen-key` // follow the interactive command line to create your private key.
Remember that, the email you entered must be the same as you set with your git account.
`git config --global user.signingkey <8bytes HEX value from gpg's public key>`
Note that there is no '=' after signingkey
One last step to go
`git tag -s "v1.0" -m "RTM v1.0"`
If you are using github(I highly recommend it, actually, I'm recommending git) service, another command to go,
`git push --tags`
Push the tags to server.