Merge branch 'update-rake-gem' into 'master'

Update rake gem to 2.2.3

See merge request dxg/unl-resource-scheduler!18

Gemfile

@@ -10,6 +10,7 @@ gem 'bcrypt'
 gem 'unicorn'
 gem 'pony'
 gem 'rest-client'
+gem 'rack', '2.2.3'
 gem 'rack-cas'
 gem 'icalendar'
 

Gemfile.lock

@@ -81,7 +81,7 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (4.0.3)
-    rack (2.1.1)
+    rack (2.2.3)
     rack-cas (0.16.1)
       addressable (~> 2.3)
       nokogiri (~> 1.5)
@@ -145,6 +145,7 @@ DEPENDENCIES
   icalendar
   mysql2
   pony
+  rack (= 2.2.3)
   rack-cas
   rest-client
   shotgun