Merge pull request #274 from 18F/upgrade-puma

Upgrade puma so it builds on OS X 10.11 OK

Author: yozlet

Diff for: Gemfile.lock

@@ -154,7 +154,7 @@ GEM
     pry-byebug (3.2.0)
       byebug (~> 5.0)
       pry (~> 0.10)
-    puma (2.13.4)
+    puma (2.15.3)
     rack (1.5.5)
     rack-protection (1.5.3)
       rack
@@ -248,4 +248,4 @@ DEPENDENCIES
   stretchy
 
 BUNDLED WITH
-   1.10.5
+   1.11.2