Add screen locker config

herbstluftwm/.config/herbstluftwm/autostart

@@ -73,6 +73,8 @@ hc keybind $Mod-b spawn hlwm-run-or-raise Conkeror conkeror
 # frame. Start an Emacs daemon if necessary.
 hc keybind $Mod-t spawn hlwm-run-or-raise Emacs \
    emacsclient --create-frame --alternate-editor=''
+# Lock the screen with C-M-l.
+hc keybind Control-Mod1-l spawn i3lock --color 000000
 
 # Since I use the colemak keyboard layout, hjkl doesn't make much
 # sense. I use neio instead since that is almost in the same place