add notification for new post in thread

util.lua

@@ -9,6 +9,7 @@ local Avatars = require("models").Avatars
 local Users = require("models").Users
 local Posts = require("models").Posts
 local PostHistory = require("models").PostHistory
+local Threads = require("models").Threads
 
 local babycode = require("lib.babycode")
 
@@ -103,6 +104,16 @@ function util.split_sentences(sentences, max_sentences)
   return util.s_split(sentences, ".", max_sentences or 2, true, false)
 end
 
+---@return string
+function util.get_post_url(req, post_id)
+  local post = Posts:find({id = post_id})
+  if not post then return "" end
+  local thread = Threads:find({id = post.thread_id})
+  if not thread then return "" end
+  
+  return req:url_for("thread", {slug = thread.slug}, {after = post_id}) .. "#post-" .. post_id
+end
+
 function util.infobox_message(msg)
   local sentences = util.split_sentences(msg)
   if #sentences == 1 then