class PromoCode < ActiveRecord::Base
    scope :by_tag_ids, ->(ids) { with_tags(ids) }

    def self.ransackable_scopes(auth_object = nil)
      [:by_tag_ids]
    end
  end

  ActiveAdmin.register PromoCode do
    filter :by_tag_ids, as: :string, label: '标签ID'
  end

Node was installed at

   /usr/local/bin/node

npm was installed at

   /usr/local/bin/npm

Make sure that /usr/local/bin is in your $PATH.

java version "1.8.0_20"
Java(TM) SE Runtime Environment (build 1.8.0_20-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.20-b23, mixed mode)

# app/controllers/users_controller.rb
class UsersController < ApplicationController

  def index
    @users = User.where(active: true).order(:last_login_at)
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  scope :active, -> { where(active: true) }
  scope :by_last_login_at, -> { order(:lasst_login_at) }

end

# app/controllers/users_controller.rb
class UsersController < ApplicationController

  def index
    @users = User.active.by_last_login_at
  end

end

<!-- app/views/posts/show.html.erb -->
...
<h2>
  <%= "#{@comments.count} Comment#{@comments.count == 1 ? '' : 's'}" %>
</h2>
...

# app/helpers/comments_helper.rb
module CommentsHelper
  def comments_count(comments)
    "#{comments.count} Comment#{comments.count == 1 ? '' : 's'}"
  end
end

<!-- app/views/posts/show.html.erb -->
<h2>
  <%= comments_count(@comments) %>
</h2>

# app/models/topic.rb
class Topic < ActiveRecord::Base

  def self.r_topics(questions)
    rt = []

    questions.each do |q|
      topics = q.topics

      topics.each do |t|
        if t.enabled?
          rt << t
        end
      end
    end

    Topic.where(id: rt)
  end

end

# app/models/topic.rb
class Topic < ActiveRecord::Base

  def self.related(questions)
    related_topics = []

    questions.each do |question|
      topics = question.topics

      topics.each do |topic|
        if topic.enabled?
          related_topics << topic
        end
      end
    end

    Topic.where(id: related_topics)
  end

end

# app/services/charge_user.rb
class ChargeUser

  def self.perform(user, amount)
    return false unless user.enabled?

    PaymentGateway.charge(user.account_id, amount)
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  def disabled?
    !enabled?
  end

end

# app/services/charge_user.rb
class ChargeUser

  def self.perform(user, amount)
    return false if user.disabled?

    PaymentGateway.charge(user.account_id, amount)
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  def enable!
    update(enabled: true)
  end

end

# app/controllers/users_controller.rb
class UsersController < ApplicationController

  def enable
    user = User.find(params[:id])

    if user.disabled?
      user.enable!
      message = "User enabled"
    else
      message = "User already disabled"
    end

    redirect_to user_path(user), notice: message
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  def enable!
    if disabled?
      update(enabled: true)
    end
  end

end

# app/controllers/users_controller.rb
class UsersController < ApplicationController

  def enable
    user = User.find(params[:id])

    if user.enable!
      message = "User enabled"
    else
      message = "User already disabled"
    end

    redirect_to user_path(user), notice: message
  end

end

# app/controllers/posts_controller.rb
class PostsController < ApplicationController

  def destroy
    post = Post.find(params[:id])

    if post.enabled? && (user.own_post?(post) || user.admin?)
      post.destroy
      message = "Post destroyed."
    else
      message = "You're not allow to destroy this post."
    end

    redirect_to posts_path, notice: message
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  def can_destroy_post?(post)
    post.enabled? && (own_post?(post) || admin?)
  end

end

# app/controllers/posts_controller.rb
class PostsController < ApplicationController

  def destroy
    post = Post.find(params[:id])

    if user.can_destroy_post?(post)
      post.destroy
      message = "Post destroyed."
    else
      message = "You're not allow to destroy this post."
    end

    redirect_to posts_path, notice: message
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  def full_name
    "#{self.first_name} #{self.last_name}"
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  def full_name
    "#{first_name} #{last_name}"
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  def full_name
    if name
      name
    else
      "No name"
    end
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  def full_name
    name ? name : "No name"
  end

end

# app/models/user.rb
class User < ActiveRecord::Base

  def full_name
    name || "No name"
  end

end

<!-- app/views/projects/show.html.erb -->
...
<h3 style="font-size:20px;letter-spacing:normal;color:#95d60a;line-height:100%;margin:0;font-family:'Proxima Nova';">
  SECRET PROJECT
</h3>
...

// app/assets/stylesheets/application.css
.project-title {
    font-size: 20px;
    letter-spacing: normal;
    color: #95d60a; 
    line-height: 100%;
    margin: 0;
    font-family:'Proxima Nova';
}

<!-- app/views/projects/show.html.erb -->
...
<h3 class="project-title">
  SECRET PROJECT
</h3>
...

<!-- app/views/questions/show.html.erb -->
...
<textarea rows="4" cols="50" class='wysihtml5'>
  Insert your question details here.
</textarea>
...
<script>
  $(document).ready(function(){
  $('textarea.wysihtml5').wysihtml5({
    "font-styles": true, //Font styling, e.g. h1, h2, etc. Default true.
    "emphasis": true, //Italics, bold, etc. Default true.
    "lists": true, //(Un)ordered lists, e.g. Bullets, Numbers. Default true.
    "html": false, //Button which allows you to edit the generated HTML. Default false.
    "link": true, //Button to insert a link. Default true.
    "image": true, //Button to insert an image. Default true.
    "color": true //Button to change color of font. Default true.
  });
});
<script>

// app/assets/javascripts/application.js
...
$(document).ready(function(){
  $('textarea.wysihtml5').wysihtml5({
    "font-styles": true, //Font styling, e.g. h1, h2, etc. Default true.
    "emphasis": true, //Italics, bold, etc. Default true.
    "lists": true, //(Un)ordered lists, e.g. Bullets, Numbers. Default true.
    "html": false, //Button which allows you to edit the generated HTML. Default false.
    "link": true, //Button to insert a link. Default true.
    "image": true, //Button to insert an image. Default true.
    "color": true //Button to change color of font. Default true.
  });
});
...

<!-- app/views/questions/show.html.erb -->
...
<textarea rows="4" cols="50" class='wysihtml5'>
  Insert your question details here.
</textarea>
...

# app/services/find_or_create_topic.rb
class FindOrCreateTopic
  ...
  def self.perform(user, name)
    find(user, sluggify(name)) || create(user, name)
  end
  ...
end

# app/services/find_or_create_topic.rb
class FindOrCreateTopic
  ...
  def self.perform(user, name)
    slug = sluggify(name)
    find(user, slug) || create(user, name)
  end
  ...
end

# lib/tasks/recalculate_badges_for_users.rake
namespace :users do

  desc "Recalculates Badges for Users"
  task recalculate_badges: :environment do
    user_count = User.count

    User.find_each do |user|
      puts "#{index}/#{user_count} Recalculating Badges for: #{user.email}"

      if user.questions_with_negative_votes >= 1 || user.answers_with_negative_votes >= 1
        user.grant_badge('Critic')
      end

      user.answers.find_each do |answer|
        question   = answer.question
        next unless answer && question

        days       = answer.created_at - question.created_at
        days_count = (days / 1.day).round

        if (days_count >= 60) && (question.vote_count >= 5)
          grant_badge('Necromancer') && return
        end
      end
    end
  end

end

# app/services/recalculate_badge.rb
class RecalculateBadge
  attr_reader :user

  def initialize(user)
    @user = user
  end

  def grant_citric
    if grant_citric?
      user.grant_badge('Critic')
    end
  end

  def grant_necromancer
    user.answers.find_each do |answer|
      question = answer.question
      next unless answer && question

      if grant_necromancer?(answer, question)
        grant_badge('Necromancer') && return
      end
    end
  end

  protected

    def grant_citric?
      (user.questions_with_negative_votes >= 1) ||
      (user.answers_with_negative_votes >= 1)
    end

    def days_count(answer, question)
      days = answer.created_at - question.created_at
      (days / 1.day).round
    end

    def grant_necromancer?(answer, question)
      (days_count(answer,question) >= 60) &&
      (question.vote_count >= 5)
    end

end

# lib/tasks/recalculate_badges_for_users.rake
namespace :users do

  desc "Recalculates Badges for Users"
  task recalculate_badges: :environment do
    user_count = User.count

    User.find_each do |user|
      puts "#{index}/#{user_count} Recalculating Badges for: #{user.email}"
      task = RecalculateBadge.new(user)
      task.grant_citric
      task.grant_necromancer
    end
  end

end