diff --git a/Gemfile.lock b/Gemfile.lock
index 0a93e13..5b5d141 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -205,8 +205,8 @@ GEM
       minitest (>= 5.1)
       securerandom (>= 0.3)
       tzinfo (~> 2.0, >= 2.0.5)
-    addressable (2.8.7)
-      public_suffix (>= 2.0.2, < 7.0)
+    addressable (2.9.0)
+      public_suffix (>= 2.0.2, < 8.0)
     amazing_print (1.6.0)
     base64 (0.2.0)
     bcp47_spec (0.2.1)
@@ -270,7 +270,7 @@ GEM
       ostruct (>= 0.2)
     optimist (3.1.0)
     ostruct (0.6.0)
-    public_suffix (6.0.1)
+    public_suffix (6.0.2)
     puma (6.6.0)
       nio4r (~> 2.0)
     racc (1.8.1)
@@ -384,7 +384,7 @@ DEPENDENCIES
   rdf-xsd!
   rspec (~> 3.12)
   rspec-its (~> 1.3)
-  shotgun (>= 0.9.2)
+  shotgun (~> 0.9, >= 0.9.2)
   sinatra-rdf!
   syntax
   yard (~> 0.9, >= 0.9.36)