Upgrade rack-protection to workaround issues with recent Chrome updates

Fixes #335

Author: pascalw

Gemfile

@@ -43,3 +43,4 @@ gem "sinatra-contrib", ">= 1.4.2"
 gem "sinatra-flash", "~> 0.3.0"
 gem "thread", "~> 0.1.3"
 gem "will_paginate", "~> 3.0", ">= 3.0.5"
+gem "rack-protection", "~> 1.5.3"

Gemfile.lock

@@ -78,7 +78,7 @@ GEM
       byebug (~> 2.2)
       pry (~> 0.9.12)
     rack (1.5.2)
-    rack-protection (1.5.1)
+    rack-protection (1.5.3)
       rack
     rack-ssl (1.4.1)
       rack
@@ -172,6 +172,7 @@ DEPENDENCIES
   nokogiri (~> 1.6)
   pg (~> 0.17.1)
   pry-byebug (~> 1.2)
+  rack-protection (~> 1.5.3)
   rack-ssl (~> 1.4.1)
   rack-test (~> 0.6.2)
   racksh (~> 1.0)