Update gems

Gemfile.lock

@@ -6,7 +6,7 @@ GEM
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
-    autoprefixer-rails (8.4.1)
+    autoprefixer-rails (8.6.3)
       execjs
     coffee-script (2.4.1)
       coffee-script-source
@@ -25,7 +25,7 @@ GEM
       standalone_typograf (>= 3.0.1)
       unicode_utils (>= 1.4)
     execjs (2.7.0)
-    ffi (1.9.23)
+    ffi (1.9.25)
     i18n (1.0.1)
       concurrent-ruby (~> 1.0)
     jquery-cdn (3.3.1)
@@ -38,11 +38,11 @@ GEM
     mini_portile2 (2.3.0)
     minitest (5.11.3)
     mustermann (1.0.2)
-    nokogiri (1.8.2)
+    nokogiri (1.8.3)
       mini_portile2 (~> 2.3.0)
     r18n-core (3.0.3)
     rack (2.0.5)
-    rack-protection (2.0.1)
+    rack-protection (2.0.3)
       rack
     rails-sass-images (1.0.3)
       dimensions (> 0)
@@ -59,15 +59,15 @@ GEM
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
-    sinatra (2.0.1)
+    sinatra (2.0.3)
       mustermann (~> 1.0)
       rack (~> 2.0)
-      rack-protection (= 2.0.1)
+      rack-protection (= 2.0.3)
       tilt (~> 2.0)
     slim (3.0.9)
       temple (>= 0.7.6, < 0.9)
       tilt (>= 1.3.3, < 2.1)
-    sprockets (3.7.1)
+    sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     standalone_typograf (3.0.2)
@@ -80,7 +80,7 @@ GEM
     tilt (2.0.8)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
-    uglifier (4.1.10)
+    uglifier (4.1.11)
       execjs (>= 0.3.0, < 3)
     unicode_utils (1.4.0)