addresses security vulnerablities identified by Github

Gemfile.lock

@@ -51,11 +51,13 @@ GEM
     byebug (10.0.2)
     coderay (1.1.2)
     concurrent-ruby (1.0.5)
+    crass (1.0.4)
     erubis (2.7.0)
     globalid (0.4.0)
       activesupport (>= 4.2.0)
     i18n (0.8.1)
-    loofah (2.0.3)
+    loofah (2.2.2)
+      crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.6.4)
       mime-types (>= 1.16, < 4)
@@ -64,7 +66,7 @@ GEM
     mime-types (3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2016.0521)
-    mini_portile2 (2.1.0)
+    mini_portile2 (2.3.0)
     minitest (5.10.1)
     minitest-reporters (1.1.7)
       ansi
@@ -74,8 +76,8 @@ GEM
     mocha (1.1.0)
       metaclass (~> 0.0.1)
     nio4r (2.0.0)
-    nokogiri (1.7.1)
-      mini_portile2 (~> 2.1.0)
+    nokogiri (1.8.2)
+      mini_portile2 (~> 2.3.0)
     pg (0.18.4)
     pry (0.11.0)
       coderay (~> 1.1.0)
@@ -105,8 +107,8 @@ GEM
     rails-dom-testing (2.0.2)
       activesupport (>= 4.2.0, < 6.0)
       nokogiri (~> 1.6)
-    rails-html-sanitizer (1.0.3)
-      loofah (~> 2.0)
+    rails-html-sanitizer (1.0.4)
+      loofah (~> 2.2, >= 2.2.2)
     railties (5.0.2)
       actionpack (= 5.0.2)
       activesupport (= 5.0.2)