Update Gem Dependencies (#57)

* Update actionview & rack

Gemfile.lock

@@ -1,15 +1,15 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    actionview (5.1.5)
-      activesupport (= 5.1.5)
+    actionview (5.2.1)
+      activesupport (= 5.2.1)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activesupport (5.1.5)
+    activesupport (5.2.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
-      i18n (~> 0.7)
+      i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
     aws-sdk (2.1.11)
@@ -25,8 +25,8 @@ GEM
     cf-app-utils (0.4)
     coderay (1.1.0)
     columnize (0.9.0)
-    concurrent-ruby (1.0.5)
-    crass (1.0.3)
+    concurrent-ruby (1.1.3)
+    crass (1.0.4)
     diff-lcs (1.2.5)
     dotenv (2.0.2)
     elasticsearch (1.1.2)
@@ -54,7 +54,7 @@ GEM
     liquid (3.0.3)
     liquify (0.2.7)
       liquid (>= 2.2.2)
-    loofah (2.2.2)
+    loofah (2.2.3)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.0)
@@ -70,7 +70,7 @@ GEM
     mustermann19 (0.4.4)
       enumerable-lazy
     newrelic_rpm (3.18.1.330)
-    nokogiri (1.8.2)
+    nokogiri (1.8.5)
       mini_portile2 (~> 2.3.0)
     oj (2.12.13)
     padrino (0.13.3.4)
@@ -119,7 +119,7 @@ GEM
       byebug (~> 5.0)
       pry (~> 0.10)
     puma (3.10.0)
-    rack (1.6.5)
+    rack (1.6.11)
     rack-protection (1.5.4)
       rack
     rack-test (0.6.3)