```ruby
Gem::Specification.new do |s|
  s.name        = "letter_opener"
  s.version     = "1.7.0"
  s.author      = "Ryan Bates"
  s.email       = "ryan@railscasts.com"
  s.homepage    = "http://github.com/ryanb/letter_opener"
  s.summary     = "Preview mail in browser instead of sending."
  s.description = "When mail is sent from your application, Letter Opener will open a preview in the browser instead of sending."
  s.license     = "MIT"

  s.files        = Dir["{lib,spec}/**/*", "[A-Z]*"] - ["Gemfile.lock"]
  s.require_path = "lib"

  s.add_dependency 'launchy', '~> 2.2'
  s.add_development_dependency 'rspec', '~> 3.5.0'
  s.add_development_dependency 'mail', '~> 2.6.0'

  s.rubyforge_project = s.name
  s.required_rubygems_version = ">= 1.3.4"
end
```

Add CHANGELOG, bug tracker, code metadata
user
```ruby
Gem::Specification.new do |s|
  s.name        = "letter_opener"
  s.version     = "1.7.0"
  s.author      = "Ryan Bates"
  s.email       = "ryan@railscasts.com"
  s.homepage    = "http://github.com/ryanb/letter_opener"
  s.summary     = "Preview mail in browser instead of sending."
  s.description = "When mail is sent from your application, Letter Opener will open a preview in the browser instead of sending."
  s.license     = "MIT"

  s.files        = Dir["{lib,spec}/**/*", "[A-Z]*"] - ["Gemfile.lock"]
  s.require_path = "lib"

  s.add_dependency 'launchy', '~> 2.2'
  s.add_development_dependency 'rspec', '~> 3.5.0'
  s.add_development_dependency 'mail', '~> 2.6.0'

  s.required_rubygems_version = ">= 1.3.4"
  
  if s.respond_to?(:metadata)
    s.metadata['changelog_uri'] = 'https://github.com/ryanb/letter_opener/blob/master/CHANGELOG.md'
    s.metadata['source_code_uri'] = 'https://github.com/ryanb/letter_opener/'
    s.metadata['bug_tracker_uri'] = 'https://github.com/ryanb/letter_opener/issues'
  end
end
```
assistant