#model

class Post < ActiveRecord::Base
  extend FriendlyId 
  friendly_id :title, use: :slugged
  belongs_to :members, :class_name => 'Member', :foreign_key => 'member_id'
  attr_accessible :description, :title, :image, :in_slider, :crop_x, :crop_y, :crop_w, :crop_h, :member_id, :ruso, :rus_lad
  attr_accessor :crop_x, :crop_y, :crop_w, :crop_h
  after_update :crop_image
  mount_uploader :image, ImageUploader
  validates :title, :description, :image, :presence => true
  scope :slider, where(:in_slider => true).limit(3)


  def crop_image
    image.recreate_versions! if crop_x.present?
  end

end


#controller

class PostsController < ApplicationController
  def index
    @posts = Post.page(params[:controller]).per(3)
  end
end


#index

<ul class="news-list">
  <ul class="list">
    <% @posts.each do |post| %>
    <li class="post">
      <div class="news-image"><a href="<%= post_path(post) %>"><img src="<%= post.image.thumb.url %>"></a></div>
      <div class="wrap">
        <div class="title"><a href="<%= post_path(post) %>"><%= post.title %></a> </div>
        <div class="desc"><%= truncate(post.description.strip_tags, :length => 180, :separator => ' ') %></div>
      </div>
    </li>
    <hr>
    <% end %>
  </ul>
  <% paginate @posts %>
</ul>