How can I have zsh as my default shell?
Everybody on the system has to use bash as login shell, because this allows us to put a standard configuration into each account. This remains the default shell of a User.
But don't worry, it's no problem to change the shell for all further operations after the login.
Create a backup of your ~/.bashrc, as it will be replaced to start zsh and not do anything else
cp ~/.bashrc ~/.bashrc.bak
Replace the content of ~/.bashrc with the following commands:
if shopt -q login_shell; then export SHELL=/bin/zsh exec /bin/zsh fi