diff --git a/Gemfile b/Gemfile
index d4eaeb918..ab44a5042 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,29 +1,35 @@
 source "https://rubygems.org"
 
-git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
-
-# test
 gem 'rake'
-gem 'minitest', '~> 5.12'
-gem 'minitest-reporters'
 gem 'rack'
 gem 'i18n'
 
 gem 'oj', require: false     # false is for testing with or without it
 
-gem 'rubocop', '~> 0.82.0'
-gem 'rubocop-performance', '~> 1.5.0'
-gem 'simplecov', require: false
-gem 'codecov', :require => false
-
-# development
-# gem 'slim'
-# gem 'haml'
+gem 'puma'
 
-# benchmark/profiling
-# gem 'benchmark-ips'
-# gem 'kalibera'
-# gem 'memory_profiler'
+group :test do
+  gem 'rubocop', '~> 0.82.0'
+  gem 'rubocop-performance', '~> 1.5.0'
+  gem 'simplecov', require: false
+  gem 'codecov', require:  false
+  gem 'minitest'
+  gem 'minitest-reporters'
+end
 
 # docs server
-gem "github-pages", '204', group: :jekyll_plugins
+gem "github-pages", '206', group: :jekyll_plugins
+
+group :apps do
+  gem 'sinatra'
+  gem 'sinatra-contrib'
+  # gem 'slim'
+  # gem 'haml'
+end
+
+# group :performance do
+  # benchmark/profiling
+  # gem 'benchmark-ips'
+  # gem 'kalibera'
+  # gem 'memory_profiler'
+# end
diff --git a/Gemfile.lock b/Gemfile.lock
index 3ffa2f6f5..3810b800c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (6.0.3.1)
+    activesupport (6.0.3.2)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
@@ -11,6 +11,7 @@ GEM
       public_suffix (>= 2.0.2, < 5.0)
     ansi (1.5.0)
     ast (2.4.1)
+    backports (3.18.1)
     builder (3.2.4)
     codecov (0.1.17)
       json
@@ -39,9 +40,9 @@ GEM
     ffi (1.13.1)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
-    github-pages (204)
+    github-pages (206)
       github-pages-health-check (= 1.16.1)
-      jekyll (= 3.8.5)
+      jekyll (= 3.8.7)
       jekyll-avatar (= 0.7.0)
       jekyll-coffeescript (= 1.1.1)
       jekyll-commonmark-ghpages (= 0.1.6)
@@ -80,7 +81,7 @@ GEM
       mercenary (~> 0.3)
       minima (= 2.5.1)
       nokogiri (>= 1.10.4, < 2.0)
-      rouge (= 3.13.0)
+      rouge (= 3.19.0)
       terminal-table (~> 1.4)
     github-pages-health-check (1.16.1)
       addressable (~> 2.3)
@@ -95,7 +96,7 @@ GEM
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
     jaro_winkler (1.5.4)
-    jekyll (3.8.5)
+    jekyll (3.8.7)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
@@ -218,7 +219,11 @@ GEM
       builder
       minitest (>= 5.0)
       ruby-progressbar
+    multi_json (1.14.1)
     multipart-post (2.1.1)
+    mustermann (1.1.1)
+      ruby2_keywords (~> 0.0.1)
+    nio4r (2.5.2)
     nokogiri (1.10.9)
       mini_portile2 (~> 2.4.0)
     octokit (4.18.0)
@@ -231,14 +236,18 @@ GEM
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (3.1.1)
-    rack (2.2.2)
+    puma (4.3.5)
+      nio4r (~> 2.0)
+    rack (2.2.3)
+    rack-protection (2.0.8.1)
+      rack
     rainbow (3.0.0)
     rake (13.0.1)
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     rexml (3.2.4)
-    rouge (3.13.0)
+    rouge (3.19.0)
     rubocop (0.82.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
@@ -252,6 +261,7 @@ GEM
     ruby-enum (0.8.0)
       i18n
     ruby-progressbar (1.10.1)
+    ruby2_keywords (0.0.2)
     rubyzip (2.3.0)
     safe_yaml (1.0.5)
     sass (3.7.4)
@@ -266,32 +276,48 @@ GEM
       docile (~> 1.1)
       simplecov-html (~> 0.11)
     simplecov-html (0.12.2)
+    sinatra (2.0.8.1)
+      mustermann (~> 1.0)
+      rack (~> 2.0)
+      rack-protection (= 2.0.8.1)
+      tilt (~> 2.0)
+    sinatra-contrib (2.0.8.1)
+      backports (>= 2.8.2)
+      multi_json
+      mustermann (~> 1.0)
+      rack-protection (= 2.0.8.1)
+      sinatra (= 2.0.8.1)
+      tilt (~> 2.0)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     thread_safe (0.3.6)
+    tilt (2.0.10)
     typhoeus (1.4.0)
       ethon (>= 0.9.0)
     tzinfo (1.2.7)
       thread_safe (~> 0.1)
     unicode-display_width (1.7.0)
     url (0.3.2)
-    zeitwerk (2.3.0)
+    zeitwerk (2.3.1)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   codecov
-  github-pages (= 204)
+  github-pages (= 206)
   i18n
-  minitest (~> 5.12)
+  minitest
   minitest-reporters
   oj
+  puma
   rack
   rake
   rubocop (~> 0.82.0)
   rubocop-performance (~> 1.5.0)
   simplecov
+  sinatra
+  sinatra-contrib
 
 BUNDLED WITH
    2.1.4