diff --git a/Gemfile.lock b/Gemfile.lock
index 3ebdb4a..10e2aaf 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -5,7 +5,6 @@ GEM
       addressable (~> 2.7)
     addressable (2.7.0)
       public_suffix (>= 2.0.2, < 5.0)
-    backports (3.17.1)
     coderay (1.1.2)
     descendants_tracker (0.0.4)
       thread_safe (~> 0.3, >= 0.3.1)
@@ -52,7 +51,7 @@ GEM
     minitest-hooks (1.5.0)
       minitest (> 5.3)
     mocha (1.11.2)
-    multi_json (1.14.1)
+    multi_json (1.15.0)
     multi_xml (0.6.0)
     multipart-post (2.1.1)
     mustermann (1.1.1)
@@ -72,25 +71,24 @@ GEM
     public_suffix (4.0.4)
     puma (4.3.3)
       nio4r (~> 2.0)
-    rack (2.2.2)
-    rack-protection (2.0.8.1)
+    rack (2.2.3)
+    rack-protection (2.2.0)
       rack
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rake (13.0.1)
     rexml (3.2.4)
-    ruby2_keywords (0.0.2)
-    sinatra (2.0.8.1)
+    ruby2_keywords (0.0.5)
+    sinatra (2.2.0)
       mustermann (~> 1.0)
-      rack (~> 2.0)
-      rack-protection (= 2.0.8.1)
+      rack (~> 2.2)
+      rack-protection (= 2.2.0)
       tilt (~> 2.0)
-    sinatra-contrib (2.0.8.1)
-      backports (>= 2.8.2)
+    sinatra-contrib (2.2.0)
       multi_json
       mustermann (~> 1.0)
-      rack-protection (= 2.0.8.1)
-      sinatra (= 2.0.8.1)
+      rack-protection (= 2.2.0)
+      sinatra (= 2.2.0)
       tilt (~> 2.0)
     thread_safe (0.3.6)
     tilt (2.0.10)