Revert "Replace puma with unicorn"

This reverts commit 7af33296fc.

Gemfile

@@ -32,8 +32,8 @@ group :development, :test do
 end
 
 group :production do
+  gem 'puma'
   gem 'skylight'
-  gem 'unicorn'
 end
 
 group :test do

Gemfile.lock

@@ -93,7 +93,6 @@ GEM
     kaminari (0.16.3)
       actionpack (>= 3.0.0)
       activesupport (>= 3.0.0)
-    kgio (2.10.0)
     loofah (2.0.3)
       nokogiri (>= 1.5.9)
     mail (2.6.3)
@@ -115,6 +114,7 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)
       slop (~> 3.4)
+    puma (2.14.0)
     rack (1.6.4)
     rack-pjax (0.8.0)
       nokogiri (~> 1.5)
@@ -165,7 +165,6 @@ GEM
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rainbow (2.0.0)
-    raindrops (0.15.0)
     rake (10.4.2)
     remotipart (1.2.1)
     responders (2.1.0)
@@ -219,10 +218,6 @@ GEM
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.1)
-    unicorn (4.9.0)
-      kgio (~> 2.6)
-      rack
-      raindrops (~> 0.7)
     validates_formatting_of (0.9.0)
       activemodel
     warden (1.2.3)
@@ -245,6 +240,7 @@ DEPENDENCIES
   nokogiri
   pg
   pry
+  puma
   rails (~> 4.2.4)
   rails_12factor
   rails_admin
@@ -255,7 +251,6 @@ DEPENDENCIES
   spring
   sqlite3
   uglifier
-  unicorn
   validates_formatting_of
   webmock
 

Procfile

@@ -1 +1 @@
-web: bundle exec unicorn -p $PORT -c ./config/unicorn.rb
+web: bundle exec puma -p $PORT