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

Gem::Specification.new do |gem|
  gem.name        = 'response'
  gem.version     = '0.0.1'
  gem.authors     = [ 'Markus Schirp' ]
  gem.email       = [ 'mbj@seonic.net' ]
  gem.description = 'Build rack responses with functional style'
  gem.summary     = gem.description
  gem.homepage    = 'https://github.com/mbj/response'

  gem.require_paths    = [ 'lib' ]
  gem.files            = `git ls-files`.split("\n")
  gem.test_files       = `git ls-files -- {spec}/*`.split("\n")
  gem.extra_rdoc_files = %w[LICENSE README.md TODO]

  gem.add_dependency 'ice_nine',      '~> 0.7.0'
  gem.add_dependency 'adamantium',    '~> 0.0.6'
  gem.add_dependency 'equalizer',     '~> 0.0.4'
  gem.add_dependency 'abstract_type', '~> 0.0.3'
end
```

Add missing dependency to gemspec
user
```ruby
# -*- encoding: utf-8 -*-

Gem::Specification.new do |gem|
  gem.name        = 'response'
  gem.version     = '0.0.1'
  gem.authors     = [ 'Markus Schirp' ]
  gem.email       = [ 'mbj@seonic.net' ]
  gem.description = 'Build rack responses with functional style'
  gem.summary     = gem.description
  gem.homepage    = 'https://github.com/mbj/response'

  gem.require_paths    = [ 'lib' ]
  gem.files            = `git ls-files`.split("\n")
  gem.test_files       = `git ls-files -- {spec}/*`.split("\n")
  gem.extra_rdoc_files = %w[LICENSE README.md TODO]

  gem.add_dependency 'ice_nine',      '~> 0.7.0'
  gem.add_dependency 'adamantium',    '~> 0.0.6'
  gem.add_dependency 'equalizer',     '~> 0.0.4'
  gem.add_dependency 'abstract_type', '~> 0.0.3'
  gem.add_dependency 'composition',   '~> 0.0.1'
end
```
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