ruby

class AddConstraintsToUsers < ActiveRecord::Migration[6.1]
  def change
    # Null constraints
    change_column_null :users, :email, false
    change_column_null :users, :username, false

class RevenueStat
  DEFAULT_RANGE = 30.days

  def initialize(account, range: DEFAULT_RANGE)
    @account = account
    @range = range

require "sidekiq/api"

class QueueDepthGuard
  class QueueSaturated < StandardError
    attr_reader :queue, :depth

<div class="search-page">
  <div class="search-header mb-6">
    <h1 class="text-2xl font-bold mb-4">Search Posts</h1>

    <%= form_with url: posts_path,
        method: :get,

# Basic Ractor usage
ractor = Ractor.new do
  # This runs in parallel, isolated from main thread
  result = heavy_computation
  result
end

class SignupsController < ApplicationController
  def new
    @user = User.new
  end

  def create

class Comment < ApplicationRecord
  belongs_to :commentable, polymorphic: true
  belongs_to :author, class_name: "User"

  scope :visible, -> { where(deleted_at: nil).order(:created_at) }

class Comment < ApplicationRecord
  belongs_to :account
  belongs_to :author, class_name: "User"

  validates :body, presence: true

class ProductsController < ApplicationController
  PER_PAGE = 24

  def index
    @page = [params[:page].to_i, 1].max
    @sort = %w[name price recent].include?(params[:sort]) ? params[:sort] : "recent"

class Current < ActiveSupport::CurrentAttributes
  attribute :user, :tenant, :request_id, :ip_address

  def user_display
    user&.email || "system"
  end

module Paginatable
  extend ActiveSupport::Concern

  included do
    before_action :set_pagination_params, only: [:index]
  end

class CreatePostService
  def initialize(author:, params:)
    @author = author
    @params = params
  end