remove thin from production env. Use unicorn for foreman

Gemfile

@@ -71,7 +71,6 @@ gem "redcarpet",     "~> 2.2.2"
 gem "github-markup", "~> 0.7.4", require: 'github/markup'
 # Servers
-gem "thin", '~> 1.5.0'
 gem "unicorn", "~> 4.4.0"
 # Issue tags

Gemfile.lock

@@ -144,7 +144,6 @@ GEM
     colorize (0.5.8)
     connection_pool (1.0.0)
     crack (0.3.1)
-    daemons (1.1.9)
     devise (2.1.2)
       bcrypt-ruby (~> 3.0)
       orm_adapter (~> 0.1)
@@ -437,10 +436,6 @@ GEM
     test_after_commit (0.0.1)
     therubyracer (0.10.2)
       libv8 (~> 3.3.10)
-    thin (1.5.0)
-      daemons (>= 1.0.9)
-      eventmachine (>= 0.12.6)
-      rack (>= 1.0.0)
     thor (0.16.0)
     tilt (1.3.3)
     timers (1.0.2)
@@ -547,7 +542,6 @@ DEPENDENCIES
   stamp
   test_after_commit
   therubyracer
-  thin (~> 1.5.0)
   uglifier (~> 1.3.0)
   unicorn (~> 4.4.0)
   webmock

Procfile

-web: bundle exec rails s -p $PORT
+web: bundle exec unicorn_rails -p $PORT
 worker: bundle exec sidekiq -q post_receive,mailer,system_hook,common,default