```ruby
# coding: utf-8
lib = File.expand_path('../lib', __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
require 'noir/version'

Gem::Specification.new do |spec|
  spec.name          = "noir"
  spec.version       = Noir::VERSION
  spec.authors       = ["atton"]
  spec.email         = ["e115763@gmail.com"]
  spec.summary       = %q{Utilities for atton.}
  spec.description   = %q{Untility commands with completion for atton.}
  spec.homepage      = "http://github.com/atton-/noir"
  spec.license       = "MIT"

  spec.files         = `git ls-files -z`.split("\x0")
  spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
  spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
  spec.require_paths = ["lib"]

  spec.required_ruby_version = '>= 1.9.2'

  spec.add_development_dependency 'bundler', '~> 1.7'
  spec.add_development_dependency 'rake',    '10.4.2'
  spec.add_development_dependency 'rspec',   '3.2.0'
  spec.add_development_dependency 'pry',     '0.10.1'
end
```

Downgrade bundler version for compatible to 2.1.2
user
```ruby
# coding: utf-8
lib = File.expand_path('../lib', __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
require 'noir/version'

Gem::Specification.new do |spec|
  spec.name          = "noir"
  spec.version       = Noir::VERSION
  spec.authors       = ["atton"]
  spec.email         = ["e115763@gmail.com"]
  spec.summary       = %q{Utilities for atton.}
  spec.description   = %q{Untility commands with completion for atton.}
  spec.homepage      = "http://github.com/atton-/noir"
  spec.license       = "MIT"

  spec.files         = `git ls-files -z`.split("\x0")
  spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
  spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
  spec.require_paths = ["lib"]

  spec.required_ruby_version = '>= 1.9.2'

  spec.add_development_dependency 'bundler', '~> 1.6'
  spec.add_development_dependency 'rake',    '10.4.2'
  spec.add_development_dependency 'rspec',   '3.2.0'
  spec.add_development_dependency 'pry',     '0.10.1'
end
```
assistant