Update gems

Gemfile.lock

@@ -10,6 +10,7 @@ GEM
     json (1.8.0)
     kgio (2.8.0)
     mini_portile (0.5.1)
+    multi_json (1.7.9)
     nokogiri (1.6.0)
       mini_portile (~> 0.5.0)
     pg (0.16.0)
@@ -20,17 +21,17 @@ GEM
       rack (>= 1.0)
     raindrops (0.11.0)
     sass (3.2.10)
-    sequel (4.0.0)
+    sequel (4.1.1)
     sinatra (1.4.3)
       rack (~> 1.4)
       rack-protection (~> 1.4)
       tilt (~> 1.3, >= 1.3.4)
-    sinatra-contrib (1.4.0)
+    sinatra-contrib (1.4.1)
       backports (>= 2.0)
-      eventmachine
+      multi_json
       rack-protection
       rack-test
-      sinatra (~> 1.4.2)
+      sinatra (~> 1.4.0)
       tilt (~> 1.3)
     sinatra-reloader (1.0)
       sinatra-contrib