Rakefile in how_is-18.0.4 vs Rakefile in how_is-18.0.5

@@ -1,24 +1,28 @@
 # frozen_string_literal: true
 
-require 'bundler/gem_tasks'
-require 'rspec/core/rake_task'
-require 'timecop'
-require './spec/vcr_helper.rb'
-require 'how_is'
+require "bundler/gem_tasks"
+require "rspec/core/rake_task"
+require "timecop"
+require "./spec/vcr_helper.rb"
+require "how_is"
 
 RSpec::Core::RakeTask.new(:spec) do |t|
   # Warning.warn() was added in Ruby 2.4.0, so don't use -w on older versions.
-  t.ruby_opts = '-w -r./spec/capture_warnings.rb' if RUBY_VERSION >= '2.4.0'
+  t.ruby_opts = "-w -r./spec/capture_warnings.rb" if RUBY_VERSION >= "2.4.0"
 end
 
 task :default => :spec
 
+task :generate_changelog do
+  sh "github_changelog_generator"
+end
+
 # Helper functions used later in the Rakefile.
 class HelperFunctions
   def self.freeze_time(&_block)
-    date = DateTime.parse('2016-11-01').new_offset(0)
+    date = DateTime.parse("2016-11-01").new_offset(0)
     Timecop.freeze(date) do
       yield
     end
   end
 
@@ -29,39 +33,54 @@
       options = {
         repository: repository,
         format: format,
       }
 
-      cassette = repository.tr('/', '-')
+      cassette = repository.tr("/", "-")
       VCR.use_cassette(cassette) do
         report = HowIs.generate_report(**options)
       end
 
       filename = "#{cassette}-report.#{format}"
       path = File.expand_path("spec/data/#{filename}", __dir__)
-      File.open(path, 'w') do |f|
+      File.open(path, "w") do |f|
         f.puts report
         # HACK: Trailing newline is missing, otherwise.
-        f.puts if format == 'html'
+        f.puts if format == "html"
       end
     end
   end
 end
 
 namespace :generate_reports do
-  desc 'Generate example HTML reports.'
+  desc "Generate example HTML reports."
   task :html do
     %w[
       how-is/example-repository
       how-is/example-empty-repository
     ].each do |repo|
-      HelperFunctions.generate_report(repo, 'html')
+      HelperFunctions.generate_report(repo, "html")
     end
   end
 
-  desc 'Generate example JSON reports.'
+  desc "Generate example JSON reports."
   task :json do
-    HelperFunctions.generate_report('how-is/example-repository', 'json')
+    HelperFunctions.generate_report("how-is/example-repository", "json")
   end
 
   task :all => [:html, :json]
+end
+
+desc "List new contributors. Lists committers with no earlier commits then "\
+     "given since_date (as %Y-%m-%d). Defaults to first of current month."
+task :new_contributors, [:user, :repo, :since_date] => [] do |_t, args|
+  require "how_is/contributions"
+  user = args[:user] || "how-is"
+  repo = args[:repo] || "how_is"
+  since_date = args[:since_date] || Time.now.strftime("%Y-%m-01")
+
+  puts "New committers:"
+  puts Contributions.new(github: Github.new(auto_pagination: true),
+                         since_date: since_date,
+                         user: user,
+                         repo: repo).new_contributors
 end