To add a new repository:

$ git submodule add https://github.com/romkatv/powerlevel10k.git ~/.github/powerlevel10k
$ git clone --depth=1 https://github.com/romkatv/powerlevel10k.git ~/.github/powerlevel10k
$ git clone --depth=1 https://github.com/romkatv/powerlevel10k.git ${ZSH_CUSTOM:-$HOME/.oh-my-zsh/custom}/themes/powerlevel10k