Add file for user specs
user
```ruby
require 'spec_helper'

describe User do
  before(:each) do
    @user = Fabricate(:user)
  end

  describe "module/plugin inclusions (optional)" do
  end

  describe "validations" do
  end

  describe "association" do
  end

  describe "callbacks" do
  end

  describe "named scopes" do
  end

  describe "class methods" do
    describe "User#find_for_authentication" do
    end

    describe "User#find_by_login_or_id" do
    end

    describe "User#find_experts" do
    end
  end

  describe "instance methods" do
    describe "User#membership_list" do
    end

    describe "User#login=" do
    end

    describe "User#email=" do
    end

    describe "User#to_param" do
    end

    describe "User#add_preferred_tags" do
    end

    describe "User#remove_preferred_tags" do
    end

    describe "User#preferred_tags_on" do
    end

    describe "User#update_language_filter" do
    end

    describe "User#languages_to_filter" do
    end

    describe "User#is_preferred_tag?" do
    end

    describe "User#admin?" do
    end

    describe "User#age" do
    end

    describe "User#can_modify?" do
    end

    describe "User#groups" do
    end

    describe "User#member_of?" do
    end

    describe "User#role_on" do
    end

    describe "User#owner_of?" do
    end

    describe "User#mod_of?" do
    end

    describe "User#editor_of?" do
    end

    describe "User#user_of?" do
    end

    describe "User#main_language" do
    end

    describe "User#openid_login?" do
    end

    describe "User#twitter_login?" do
    end

    describe "User#has_voted?" do
    end

    describe "User#vote_on" do
    end

    describe "User#favorite?" do
    end

    describe "User#favorite" do
    end

    describe "User#logged!" do
    end

    describe "User#on_activity" do
    end

    describe "User#activity_on" do
    end

    describe "User#reset_activity_days!" do
    end

    describe "User#upvote!" do
    end

    describe "User#downvote!" do
    end

    describe "User#update_reputation" do
    end

    describe "User#reputation_on" do
    end

    describe "User#stats" do
    end

    describe "User#badges_count_on" do
    end

    describe "User#badges_on" do
    end

    describe "User#find_badge_on" do
    end

    describe "User#add_friend" do
    end

    describe "User#remove_friend" do
    end

    describe "User#followers" do
    end

    describe "User#following" do
    end

    describe "User#following?" do
    end

    describe "User#viewed_on!" do
    end

    describe "User#config_for" do
    end

    describe "User#reputation_stats" do
    end

    describe "User#has_flagged?" do
    end

    describe "User#has_requested_to_close?" do
    end

    describe "User#has_requested_to_open?" do
    end

    describe "User#generate_uuid" do
    end
  end
end
```
assistant