implement async fetching tags

Gemfile.lock

@@ -2,7 +2,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     addressable (2.3.6)
-    colorize (0.7.3)
+    colorize (0.7.4)
     descendants_tracker (0.0.4)
       thread_safe (~> 0.3, >= 0.3.1)
     faraday (0.9.0)
@@ -15,13 +15,13 @@ GEM
       multi_json (>= 1.7.5, < 2.0)
       nokogiri (~> 1.6.3)
       oauth2
-    hashie (3.3.1)
-    jwt (1.0.0)
+    hashie (3.3.2)
+    jwt (1.2.0)
     mini_portile (0.6.1)
     multi_json (1.10.1)
     multi_xml (0.5.5)
     multipart-post (2.0.0)
-    nokogiri (1.6.4)
+    nokogiri (1.6.5)
       mini_portile (~> 0.6.0)
     oauth2 (1.0.0)
       faraday (>= 0.8, < 0.10)

lib/github_changelog_generator.rb

@@ -3,6 +3,8 @@
 require 'github_api'
 require 'json'
 require 'colorize'
+require 'benchmark'
+
 require_relative 'github_changelog_generator/parser'
 require_relative 'github_changelog_generator/generator'
 require_relative 'github_changelog_generator/version'
@@ -148,8 +150,13 @@ module GitHubChangelogGenerator
 
     def generate_log_for_all_tags
       log = ''
-      @all_tags.each { |tag| self.get_time_of_tag(tag) }
 
+      # Async fetching tags:
+      threads = []
+      @all_tags.each { |tag|
+        threads << Thread.new { self.get_time_of_tag(tag) }
+      }
+      threads.each { |thr| thr.join }
 
       if @options[:verbose]
         puts "Sorting tags.."
@@ -329,10 +336,6 @@ module GitHubChangelogGenerator
         return @tag_times_hash[prev_tag['name']]
       end
 
-      if @options[:verbose]
-        puts "Getting time for tag #{prev_tag['name']}"
-      end
-
       github_git_data_commits_get = @github.git_data.commits.get @options[:user], @options[:project], prev_tag['commit']['sha']
       time_string = github_git_data_commits_get['committer']['date']
       Time.parse(time_string)