Update puma

Gemfile

@@ -76,7 +76,7 @@ gem "github-markup", "~> 0.7.4", require: 'github/markup'
 gem  "asciidoctor"
 # Servers
-gem "puma", '~> 2.1.1'
+gem "puma", '~> 2.3.0'
 # State machine
 gem "state_machine"

Gemfile.lock

@@ -306,7 +306,7 @@ GEM
       coderay (~> 1.0.5)
       method_source (~> 0.8)
       slop (~> 3.4)
-    puma (2.1.1)
+    puma (2.3.0)
       rack (>= 1.1, < 2.0)
     pygments.rb (0.4.2)
       posix-spawn (~> 0.3.6)
@@ -576,7 +576,7 @@ DEPENDENCIES
   pg
   poltergeist (~> 1.3.0)
   pry
-  puma (~> 2.1.1)
+  puma (~> 2.3.0)
   quiet_assets (~> 1.0.1)
   rack-mini-profiler
   rails (= 3.2.13)