[Feature] New option: grip-preview-host.

Close #19.

README.md

@@ -94,6 +94,9 @@ Run `M-x customize-group RET grip RET` or set the variables.
 ;; after every text change
 (setq grip-update-after-change nil)
 
+;; Preview hostname
+(setq grip-preview-host "localhost")
+
 ;; Use embedded webkit to previe
 ;; This requires GNU/Emacs version >= 26 and built with the `--with-xwidgets`
 ;; option.

grip-mode.el

@@ -83,6 +83,11 @@ When nil, only update the preview on file save."
   :type 'boolean
   :group 'grip)
 
+(defcustom grip-preview-host "localhost"
+  "Preview hostname."
+  :type 'string
+  :group 'grip)
+
 (defcustom grip-preview-use-webkit t
   "Use embedded webkit to preview.
 
@@ -134,7 +139,7 @@ Use default browser unless `xwidget' is available."
 
 (defun grip--preview-url ()
   "Return grip preview url."
-  (format "http://localhost:%d" grip--port))
+  (format "http://%s:%d" grip-preview-host grip--port))
 
 (defun grip-start-process ()
   "Render and preview with grip."