Add 'SPC p $' to run multi-term at project root

spacemacs/funcs.el

@@ -872,3 +872,8 @@ If ASCII si not provided then UNICODE is used instead."
   (delete-region (point-min) (point-max))
   (clipboard-yank)
   (deactivate-mark))
+
+(defun projectile-multi-term-in-root ()
+  "Invoke `multi-term' in the project's root."
+  (interactive)
+  (projectile-with-default-dir (projectile-project-root) (multi-term)))

spacemacs/packages.el

@@ -2534,6 +2534,7 @@ It is a string holding:
           "ps" 'projectile-switch-project))
       (evil-leader/set-key
         "p!" 'projectile-run-shell-command-in-root
+        "p$" 'projectile-multi-term-in-root
         "p&" 'projectile-run-async-shell-command-in-root
         "pc" 'projectile-compile-project
         "pD" 'projectile-dired