Update gems

Gemfile.lock

@@ -1,7 +1,7 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (5.1.3)
+    activesupport (5.1.4)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (~> 0.7)
       minitest (~> 5.1)
@@ -11,8 +11,8 @@ GEM
       coderay (>= 1.0.0)
       erubi (>= 1.0.0)
       rack (>= 0.9.0)
-    browser (2.5.0)
-    coderay (1.1.1)
+    browser (2.5.1)
+    coderay (1.1.2)
     coffee-script (2.4.1)
       coffee-script-source
       execjs
@@ -24,7 +24,7 @@ GEM
       ffi (>= 1.3.0)
     eventmachine (1.2.5)
     execjs (2.7.0)
-    exifr (1.3.1)
+    exifr (1.3.2)
     ffi (1.9.18)
     fspath (3.1.0)
     highline (1.7.8)
@@ -38,7 +38,7 @@ GEM
       image_size (~> 1.5)
       in_threads (~> 1.3)
       progress (~> 3.0, >= 3.0.1)
-    image_optim_pack (0.5.0.20170815)
+    image_optim_pack (0.5.0.20170831)
       fspath (>= 2.1, < 4)
       image_optim (~> 0.19)
     image_size (1.5.0)
@@ -46,7 +46,7 @@ GEM
     method_source (0.8.2)
     mini_portile2 (2.2.0)
     minitest (5.10.3)
-    multi_json (1.12.1)
+    multi_json (1.12.2)
     mustermann (1.0.1)
     nokogiri (1.8.0)
       mini_portile2 (~> 2.2.0)
@@ -64,7 +64,7 @@ GEM
       rack
     rack-test (0.7.0)
       rack (>= 1.0, < 3)
-    rake (12.0.0)
+    rake (12.1.0)
     rb-fsevent (0.10.2)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)