```ruby
require 'rubygems'
require 'bundler/setup'
Bundler.require(:default, :development)

# Prepare activerecord
require "active_record"

# Connect to sqlite
ActiveRecord::Base.establish_connection(
  "adapter" => "sqlite3",
  "database" => ":memory:"
)

ActiveRecord::Base.logger = Logger.new(nil)
load(File.join(File.dirname(__FILE__), 'schema.rb'))

Paperclip::Railtie.insert
Paperclip::Meta::Railtie.insert

class Image < ActiveRecord::Base
  has_attached_file :small_image,
    :storage => :filesystem,
    :path => "./spec/tmp/:style/:id.:extension",
    :url => "./spec/tmp/:style/:id.extension"

  has_attached_file :big_image,
    :storage => :filesystem,
    :path => "./spec/tmp/fixtures/tmp/:style/:id.:extension",
    :url => "./spec/tmp/fixtures/tmp/:style/:id.extension",
    :styles => { :small => "100x100#" }
end```

Use Paperclip::Glue instead of Railtie
user
```ruby
require 'rubygems'
require 'bundler/setup'
Bundler.require(:default, :development)

# Prepare activerecord
require "active_record"

# Connect to sqlite
ActiveRecord::Base.establish_connection(
  "adapter" => "sqlite3",
  "database" => ":memory:"
)

ActiveRecord::Base.logger = Logger.new(nil)
load(File.join(File.dirname(__FILE__), 'schema.rb'))

ActiveRecord::Base.send(:include, Paperclip::Glue)
Paperclip::Meta::Railtie.insert

class Image < ActiveRecord::Base
  has_attached_file :small_image,
    :storage => :filesystem,
    :path => "./spec/tmp/:style/:id.:extension",
    :url => "./spec/tmp/:style/:id.extension"

  has_attached_file :big_image,
    :storage => :filesystem,
    :path => "./spec/tmp/fixtures/tmp/:style/:id.:extension",
    :url => "./spec/tmp/fixtures/tmp/:style/:id.extension",
    :styles => { :small => "100x100#" }
end
```
assistant