def update
      @post = Post.includes(:user, :discussion).find(params[:id])
      raise Cornerstone::AccessDenied unless @post.created_by?(current_cornerstone_user)
      @discussion = @post.discussion
      flash[:notice] = "Post was successfully updated." if @post.update_attributes(params[:post])
      respond_with(@discussion, @post, :location => category_discussion_path(@discussion.category, @discussion))
    end
def update
      @post = Post.includes(:user, :discussion).find(params[:id])
      raise Cornerstone::AccessDenied unless @post.created_by?(current_cornerstone_user)
      @discussion = @post.discussion
      flash[:notice] = "Post was successfully updated." if @post.update_attributes(params[:post])
      respond_with(@discussion, @post, :location => category_discussion_path(@discussion.category, @discussion))
    end
PUT /cornerstone/discussions/:discussion_id/posts/:id