Upgraded rack gem

Author: jasnow

Gemfile.lock

@@ -201,7 +201,7 @@ GEM
     psych (3.1.0)
     public_suffix (3.0.3)
     puma (3.12.1)
-    rack (2.0.6)
+    rack (2.0.7)
     rack-livereload (0.3.17)
       rack
     rack-test (1.1.0)