use thin for development

Gemfile

@@ -15,11 +15,10 @@ gem 'pg'
 # for building JSON
 gem 'jbuilder', '~> 1.2'
 
-# HTTP server for Rack applications
-gem 'unicorn'
-
-# without this in development webrick is used
-gem "unicorn-rails"
+# HTTP server for Rack applications for staginng and production
+# See https://github.com/bigbinary/wheel/issues/43 for why unicorn is
+# not used in development.
+gem 'unicorn', group: [:staging, :production]
 
 # for authentication
 gem 'devise', '3.2.3'
@@ -65,6 +64,9 @@ gem 'haml-rails'
 
 group :development do
 
+  # application server for development
+  gem 'thin'
+
   # mutes assets pipeline log messages
   gem 'quiet_assets'
 

Gemfile.lock

@@ -80,6 +80,7 @@ GEM
       coffee-script-source
       execjs
     coffee-script-source (1.8.0)
+    daemons (1.1.9)
     delayed_job (4.0.6)
       activesupport (>= 3.0, < 5.0)
     delayed_job_active_record (4.0.3)
@@ -101,6 +102,7 @@ GEM
     email_validator (1.5.0)
       activemodel
     erubis (2.7.0)
+    eventmachine (1.0.4)
     execjs (2.2.2)
     formtastic (3.1.2)
       actionpack (>= 3.2.13)
@@ -225,6 +227,10 @@ GEM
       actionpack (>= 3.0)
       activesupport (>= 3.0)
       sprockets (>= 2.8, < 4.0)
+    thin (1.6.3)
+      daemons (~> 1.0, >= 1.0.9)
+      eventmachine (~> 1.0)
+      rack (~> 1.0)
     thor (0.19.1)
     thread_safe (0.3.4)
     tilt (1.4.1)
@@ -242,9 +248,6 @@ GEM
       kgio (~> 2.6)
       rack
       raindrops (~> 0.7)
-    unicorn-rails (2.2.0)
-      rack
-      unicorn
     warden (1.2.3)
       rack (>= 1.0)
 
@@ -276,7 +279,7 @@ DEPENDENCIES
   simplecov
   spring
   sprockets-rails (~> 2.0)
+  thin
   twitter-bootstrap-rails
   uglifier (>= 1.0.3)
   unicorn
-  unicorn-rails