Add rack attack gem.

Gemfile

@@ -120,6 +120,9 @@ gem "underscore-rails", "~> 1.4.4"
 # Sanitize user input
 gem "sanitize"
+# Protect against bruteforcing
+gem "rack-attack"
+
 group :assets do
   gem "sass-rails"
   gem "coffee-rails"

Gemfile.lock

@@ -334,6 +334,8 @@ GEM
     rack (1.4.5)
     rack-accept (0.4.5)
       rack (>= 0.4)
+    rack-attack (2.2.1)
+      rack
     rack-cache (1.2)
       rack (>= 0.4)
     rack-mini-profiler (0.1.26)
@@ -603,6 +605,7 @@ DEPENDENCIES
   poltergeist (~> 1.4.1)
   pry
   quiet_assets (~> 1.0.1)
+  rack-attack
   rack-mini-profiler
   rails (= 3.2.13)
   rails-dev-tweaks