```ruby
# -*- encoding: utf-8 -*-

libdir = File.expand_path('../lib/', __FILE__)
$:.unshift(libdir) unless $:.include?(libdir)
require 'messagebird'

Gem::Specification.new do |s|
  s.name        = 'messagebird-rest'
  s.version     = MessageBird::CLIENT_VERSION
  s.platform    = Gem::Platform::RUBY
  s.date        = Time.now
  s.summary     = "MessageBird's REST API"
  s.description = 'A simple REST API for MessageBird in Ruby'
  s.author      = 'Maurice Nonnekes'
  s.email       = 'maurice@messagebird.com'
  s.homepage    = 'https://github.com/messagebird/ruby-rest-api'
  s.license     = 'BSD-2-Clause'

  s.files        = Dir.glob("lib/**/*") + %w(LICENSE README.md)
  s.require_path = 'lib'
end
```

Add rspec as a development dependency
user
```ruby
# -*- encoding: utf-8 -*-

libdir = File.expand_path('../lib/', __FILE__)
$:.unshift(libdir) unless $:.include?(libdir)
require 'messagebird'

Gem::Specification.new do |s|
  s.name        = 'messagebird-rest'
  s.version     = MessageBird::CLIENT_VERSION
  s.platform    = Gem::Platform::RUBY
  s.date        = Time.now
  s.summary     = "MessageBird's REST API"
  s.description = 'A simple REST API for MessageBird in Ruby'
  s.author      = 'Maurice Nonnekes'
  s.email       = 'maurice@messagebird.com'
  s.homepage    = 'https://github.com/messagebird/ruby-rest-api'
  s.license     = 'BSD-2-Clause'

  s.files        = Dir.glob("lib/**/*") + %w(LICENSE README.md)
  s.require_path = 'lib'

  s.add_development_dependency 'rspec', '~> 3.8'
end
```
assistant