issue #10 fix "add tags to posts"

admin.rb

@@ -58,9 +58,12 @@ class Admin < Sinatra::Base
     @post = Post.get(params[:id])
     if @post
       if params[:post].has_key? 'tags'
-        @post.set_tags params[:post].delete('tags')
+        tags = params[:post].delete('tags')
       end
-      unless @post.update(params[:post])
+      if @post.update(params[:post])
+        @post.set_tags tags
+        @post.save
+      else
         flash.warning = 'Error at saving the post!'
         flash[:errors] = true
       end

models/post.rb

@@ -46,9 +46,6 @@ class Post
 
   # sets all tags for this post
   def set_tags new_tags
-    tags = []
-    new_tags.each do |tag_id|
-      tags << Tag.first(:id => tag_id)
-    end
+    self.tags = Tag.all(:id => new_tags)
   end
 end

views/admin_post_edit.haml

@@ -39,7 +39,7 @@
           %option{:value => account.id}=account.username
   .tags
     %label{:for => :post_tags}="Tags (#{Tag.all.count})"
-    %select{:name => 'post[tags]', :id => :post_tags, :size => 10, :multiple => true}
+    %select{:name => 'post[tags][]', :id => :post_tags, :size => 10, :multiple => true}
       - post_tags = @post.tags
       - Tag.all(:order => [:name.asc]).each do |tag|
         -if @post.has_tag tag