Can edit category descriptions, they show up in a title attribute

lib/post_revisor.rb

@@ -1,5 +1,8 @@
 require 'edit_rate_limiter'
 class PostRevisor
+
+  attr_reader :category_changed
+
   def initialize(post)
     @post = post
   end
@@ -8,6 +11,7 @@ class PostRevisor
     @user, @new_raw, @opts = user, new_raw, opts
     return false if not should_revise?
     revise_post
+    update_category_description
     post_process_post
     true
   end
@@ -76,6 +80,25 @@ class PostRevisor
     @post.save
   end
 
+  def update_category_description
+    # If we're revising the first post, we might have to update the category description
+    return unless @post.post_number == 1
+
+    # Is there a category with our topic id?
+    category = Category.where(topic_id: @post.topic_id).first
+    return unless category.present?
+
+    # If found, update its description
+    body = @post.cooked
+    matches = body.scan(/\<p\>(.*)\<\/p\>/)
+    if matches and matches[0] and matches[0][0]      
+      new_description = matches[0][0]
+      new_description = nil if new_description == I18n.t("category.replace_paragraph")
+      category.update_column(:description, new_description)
+      @category_changed = category
+    end
+  end
+
   def post_process_post
     @post.invalidate_oneboxes = true
     @post.trigger_post_process