Andrew Emelianenko

<% if @article.errors.any? %>
  <div id="error_explanation">
    <h2><%= pluralize(@article.errors.count, "error") %> prohibited this article from being saved:</h2>
    <ul>
    <% @article.errors.full_messages.each do |msg| %>
      <li><%= msg %></li>
    <% end %>
    </ul>
  </div>
<% end %>

# project.rb
has_many :tasks

# вызывать так
project = Project.first
project.tasks            # список всех тасков у проекта
project.tasks.create({ ... })  # создание нового таска

class Post
  layout :set_layout

  private
  def set_layout
    "#{category_name}_layout"
  end
end

<%= render partial: "posts/#{@post.category_name}", locals: { post: @post } %>

secret_key_base: <%= ENV['SECRET_KEY_BASE'] || 'my_super_secret_code1231243512' %>

# Enumerable status
  STATUS = {
      0 => :waiting,
      1 => :finished,
      2 => :expired,
      3 => :removed
  }

  STATUS.each do |key, status|
    define_method "#{status}!" do
      self.status = key
      self.save
    end

    define_method "#{status}?" do
      self.status == key
    end
  end

  def status?
    STATUS[self.status]
  end

object.finished! # status = 1

object.waiting? # false
object.waiting! # status = 0
object.waiting? # true

object.status? # waiting