```ruby
# -*- encoding: utf-8 -*-
$:.push File.expand_path("../lib", __FILE__)
require "cool.io/version"

Gem::Specification.new do |s|
  s.name        = "cool.io"
  s.version     = Coolio::VERSION
  s.authors     = ["Tony Arcieri", "Masahiro Nakagawa"]
  s.email       = ["tony.arcieri@gmail.com", "repeatedly@gmail.com"]
  s.homepage    = "http://coolio.github.com"
  s.summary     = "A cool framework for doing high performance I/O in Ruby"
  s.description = "Cool.io provides a high performance event framework for Ruby which uses the libev C library"
  s.extensions = ["ext/cool.io/extconf.rb", "ext/iobuffer/extconf.rb"]

  s.files         = `git ls-files`.split("\n")
  s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
  s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
  s.require_paths = ["lib"]

  s.add_development_dependency "rake-compiler", "~> 1.0"
  s.add_development_dependency "rake-compiler-dock", "~> 1.0"
  s.add_development_dependency "rspec", ">= 2.13.0"
  s.add_development_dependency "rdoc", ">= 3.6.0"
end
```

Add recommended gemspec attributes - licenses
user
```ruby
# -*- encoding: utf-8 -*-
$:.push File.expand_path("../lib", __FILE__)
require "cool.io/version"

Gem::Specification.new do |s|
  s.name        = "cool.io"
  s.version     = Coolio::VERSION
  s.authors     = ["Tony Arcieri", "Masahiro Nakagawa"]
  s.email       = ["tony.arcieri@gmail.com", "repeatedly@gmail.com"]
  s.homepage    = "http://coolio.github.com"
  s.summary     = "A cool framework for doing high performance I/O in Ruby"
  s.description = "Cool.io provides a high performance event framework for Ruby which uses the libev C library"
  s.extensions = ["ext/cool.io/extconf.rb", "ext/iobuffer/extconf.rb"]
  s.licenses   = ["MIT"]

  s.files         = `git ls-files`.split("\n")
  s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
  s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
  s.require_paths = ["lib"]

  s.add_development_dependency "rake-compiler", "~> 1.0"
  s.add_development_dependency "rake-compiler-dock", "~> 1.0"
  s.add_development_dependency "rspec", ">= 2.13.0"
  s.add_development_dependency "rdoc", ">= 3.6.0"
end
```
assistant