```ruby
require 'uri'
require 'net/http'
require 'net/https'
require 'digest/sha1'
require 'cgi'

require 'rubygems'
require 'json'

module Sendhub
end

require 'sendhub/http'
require 'sendhub/response'
require 'sendhub/client'

if defined? Rails
  if Rails.version =~ /^2./
    require 'action_mailer'
    require 'sendhub/plugins/rails2'
  elsif Rails.version =~ /^3./
    require 'sendhub/plugins/rails3'
  elsif Rails.version =~ /^4./
    require 'sendhub/plugins/rails3'
  end
end```

Add support for Rails 5.x
user
```ruby
require 'uri'
require 'net/http'
require 'net/https'
require 'digest/sha1'
require 'cgi'

require 'rubygems'
require 'json'

module Sendhub
end

require 'sendhub/http'
require 'sendhub/response'
require 'sendhub/client'

if defined? Rails
  if Rails.version =~ /^2./
    require 'action_mailer'
    require 'sendhub/plugins/rails2'
  elsif Rails.version =~ /^3./
    require 'sendhub/plugins/rails3'
  elsif Rails.version =~ /^4./
    require 'sendhub/plugins/rails3'
  elsif Rails.version =~ /^5./
    require 'sendhub/plugins/rails3'
  end
end
```
assistant