Use puma instead of unicorn

We have been using puma for all other apps on heroku and also this is default in new apps created by suspenders.

Gemfile

@@ -34,6 +34,7 @@ gem "paperclip", "~> 4.2.2"
 gem "pg"
 gem "pg_search"
 gem "pry-rails"
+gem "puma"
 gem "rack-canonical-host"
 gem "rack-rewrite", "~> 1.5.1"
 gem "rails", "~> 4.2.4"
@@ -49,7 +50,6 @@ gem "sprockets-redirect"
 gem "stripe"
 gem "stripe_event"
 gem "uglifier"
-gem "unicorn"
 gem "validates_email_format_of"
 gem "vanity", "2.0.0.beta8"
 gem "wrapped"

Gemfile.lock

@@ -161,7 +161,6 @@ GEM
     kaminari (0.16.3)
       actionpack (>= 3.0.0)
       activesupport (>= 3.0.0)
-    kgio (2.9.2)
     launchy (2.4.3)
       addressable (~> 2.3)
     loofah (2.0.3)
@@ -217,6 +216,7 @@ GEM
       slop (~> 3.4)
     pry-rails (0.3.2)
       pry (>= 0.9.10)
+    puma (2.15.3)
     quiet_assets (1.0.3)
       railties (>= 3.1, < 5.0)
     rack (1.6.4)
@@ -276,7 +276,6 @@ GEM
       activesupport (= 4.2.5)
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
-    raindrops (0.13.0)
     rake (10.5.0)
     recipient_interceptor (0.1.2)
       mail
@@ -366,10 +365,6 @@ GEM
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.1)
-    unicorn (4.8.3)
-      kgio (~> 2.6)
-      rack
-      raindrops (~> 0.7)
     validates_email_format_of (1.6.1)
       i18n
     vanity (2.0.0.beta8)
@@ -428,6 +423,7 @@ DEPENDENCIES
   pg
   pg_search
   pry-rails
+  puma
   quiet_assets
   rack-canonical-host
   rack-mini-profiler
@@ -454,7 +450,6 @@ DEPENDENCIES
   stripe_event
   timecop
   uglifier
-  unicorn
   validates_email_format_of
   vanity (= 2.0.0.beta8)
   webmock

Procfile

@@ -1,2 +1,2 @@
-web: bundle exec unicorn -p $PORT -c ./config/unicorn.rb
+web: bundle exec puma -p $PORT -C ./config/puma.rb
 worker: bundle exec rake jobs:work

config/puma.rb

@@ -0,0 +1,28 @@
+# https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server
+
+# The environment variable WEB_CONCURRENCY may be set to a default value based
+# on dyno size. To manually configure this value use heroku config:set
+# WEB_CONCURRENCY.
+#
+# Increasing the number of workers will increase the amount of resting memory
+# your dynos use. Increasing the number of threads will increase the amount of
+# potential bloat added to your dynos when they are responding to heavy
+# requests.
+#
+# Starting with a low number of workers and threads provides adequate
+# performance for most applications, even under load, while maintaining a low
+# risk of overusing memory.
+workers Integer(ENV.fetch("WEB_CONCURRENCY", 2))
+threads_count = Integer(ENV.fetch("MAX_THREADS", 2))
+threads(threads_count, threads_count)
+
+preload_app!
+
+rackup DefaultRackup
+environment ENV.fetch("RACK_ENV", "development")
+
+on_worker_boot do
+  # Worker specific setup for Rails 4.1+
+  # See: https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#on-worker-boot
+  ActiveRecord::Base.establish_connection
+end