Add changelog generator

Rakefile

@@ -1,3 +1,10 @@
+require 'rubygems'
+
+gemspec = Gem::Specification.load('lita-tox.gemspec')
+
+github_user, github_project =
+  gemspec.homepage.scan(%r{^https://github\.com/([^/]+)/([^/]+)/?$})[0]
+
 require 'bundler/gem_tasks'
 
 task default: [:spec, :lint]
@@ -12,3 +19,13 @@ RuboCop::RakeTask.new
 
 require 'yard'
 YARD::Rake::YardocTask.new
+
+desc 'Generate changelog'
+task :changelog, [:token] do |_t, args|
+  cmd = 'github_changelog_generator'
+  cmd << " -u #{github_user}"
+  cmd << " -p #{github_project}"
+  cmd << " -t #{args[:token]}" if args[:token]
+
+  sh cmd
+end

lita-tox.gemspec

@@ -29,4 +29,5 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'simplecov', '~> 0.10'
   spec.add_development_dependency 'yard', '~> 0.8'
   spec.add_development_dependency 'redcarpet', '~> 3.3'
+  spec.add_development_dependency 'github_changelog_generator', '~> 1.6'
 end