This place will primarily used for known issues and other related information.

For general information about the app, please visit www.cakebrew.com.

According to zsh guide the login shell start up files are ~/.zprofile and ~/.zlogin
so I think all the zsh user who's cakebrew cannot find brew should put the following line into ~/.zlogin (or ~/.zprofile)
export PATH=/usr/local/bin:$PATH
(/usr/local/bin can be replaced with your brew's directory)
this works for me. (I only have ~/.zshrc in the beginning)

Thanks user neoesque for this information. Read more about this problem here.