diff --git a/Gemfile b/Gemfile
index e80a3eee..70411785 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-gem 'rails', '~> 5.1.0'
+gem 'rails', '~> 5.2.1'
 gem 'sass-rails', '~> 5.0'
 gem 'coffee-rails', '~> 4.2.0'
 
@@ -23,7 +23,7 @@ gem 'jquery-ui-rails' , '~>5.0.5'
 # always possible on all platforms
 # Alternatively use --without <group> arguments to bundler to not install that group
 gem "sqlite3", group: :sqlite
-gem "mysql2", "~> 0.3.17", group: :mysql
+gem "mysql2", "~> 0.4.0", group: :mysql
 
 gem "RedCloth"
 gem "sanitize", ">=3.0.0"
diff --git a/Gemfile.lock b/Gemfile.lock
index 107ae833..0bf5717c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -3,19 +3,19 @@ GEM
   specs:
     RedCloth (4.3.2)
     aasm (3.4.0)
-    actioncable (5.1.6)
-      actionpack (= 5.1.6)
+    actioncable (5.2.1)
+      actionpack (= 5.2.1)
       nio4r (~> 2.0)
-      websocket-driver (~> 0.6.1)
-    actionmailer (5.1.6)
-      actionpack (= 5.1.6)
-      actionview (= 5.1.6)
-      activejob (= 5.1.6)
+      websocket-driver (>= 0.6.1)
+    actionmailer (5.2.1)
+      actionpack (= 5.2.1)
+      actionview (= 5.2.1)
+      activejob (= 5.2.1)
       mail (~> 2.5, >= 2.5.4)
       rails-dom-testing (~> 2.0)
-    actionpack (5.1.6)
-      actionview (= 5.1.6)
-      activesupport (= 5.1.6)
+    actionpack (5.2.1)
+      actionview (= 5.2.1)
+      activesupport (= 5.2.1)
       rack (~> 2.0)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
@@ -23,33 +23,37 @@ GEM
     actionpack-xml_parser (2.0.1)
       actionpack (>= 5.0)
       railties (>= 5.0)
-    actionview (5.1.6)
-      activesupport (= 5.1.6)
+    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)
-    activejob (5.1.6)
-      activesupport (= 5.1.6)
+    activejob (5.2.1)
+      activesupport (= 5.2.1)
       globalid (>= 0.3.6)
-    activemodel (5.1.6)
-      activesupport (= 5.1.6)
+    activemodel (5.2.1)
+      activesupport (= 5.2.1)
     activemodel-serializers-xml (1.0.2)
       activemodel (> 5.x)
       activesupport (> 5.x)
       builder (~> 3.1)
-    activerecord (5.1.6)
-      activemodel (= 5.1.6)
-      activesupport (= 5.1.6)
-      arel (~> 8.0)
-    activesupport (5.1.6)
+    activerecord (5.2.1)
+      activemodel (= 5.2.1)
+      activesupport (= 5.2.1)
+      arel (>= 9.0)
+    activestorage (5.2.1)
+      actionpack (= 5.2.1)
+      activerecord (= 5.2.1)
+      marcel (~> 0.3.1)
+    activesupport (5.2.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
     acts_as_list (0.9.15)
       activerecord (>= 3.0)
-    arel (8.0.0)
+    arel (9.0.0)
     ast (2.4.0)
     autoprefixer-rails (9.3.1)
       execjs
@@ -74,7 +78,7 @@ GEM
       coffee-script-source
       execjs
     coffee-script-source (1.12.2)
-    concurrent-ruby (1.0.5)
+    concurrent-ruby (1.1.3)
     crass (1.0.4)
     database_cleaner (1.7.0)
     diff-lcs (1.3)
@@ -112,8 +116,10 @@ GEM
       nokogiri (>= 1.5.9)
     mail (2.7.1)
       mini_mime (>= 0.1.1)
+    marcel (0.3.3)
+      mimemagic (~> 0.3.2)
     metaclass (0.0.4)
-    method_source (0.9.1)
+    method_source (0.9.2)
     mime-types (3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2016.0521)
@@ -124,7 +130,7 @@ GEM
     minitest-stub-const (0.6)
     mocha (1.7.0)
       metaclass (~> 0.0.1)
-    mysql2 (0.3.21)
+    mysql2 (0.4.10)
     nio4r (2.3.1)
     nokogiri (1.8.5)
       mini_portile2 (~> 2.3.0)
@@ -148,17 +154,18 @@ GEM
       rack (>= 1.2.0)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
-    rails (5.1.6)
-      actioncable (= 5.1.6)
-      actionmailer (= 5.1.6)
-      actionpack (= 5.1.6)
-      actionview (= 5.1.6)
-      activejob (= 5.1.6)
-      activemodel (= 5.1.6)
-      activerecord (= 5.1.6)
-      activesupport (= 5.1.6)
+    rails (5.2.1)
+      actioncable (= 5.2.1)
+      actionmailer (= 5.2.1)
+      actionpack (= 5.2.1)
+      actionview (= 5.2.1)
+      activejob (= 5.2.1)
+      activemodel (= 5.2.1)
+      activerecord (= 5.2.1)
+      activestorage (= 5.2.1)
+      activesupport (= 5.2.1)
       bundler (>= 1.3.0)
-      railties (= 5.1.6)
+      railties (= 5.2.1)
       sprockets-rails (>= 2.0.0)
     rails-controller-testing (1.0.2)
       actionpack (~> 5.x, >= 5.0.1)
@@ -171,12 +178,12 @@ GEM
       loofah (~> 2.2, >= 2.2.2)
     rails_autolink (1.1.6)
       rails (> 3.1)
-    railties (5.1.6)
-      actionpack (= 5.1.6)
-      activesupport (= 5.1.6)
+    railties (5.2.1)
+      actionpack (= 5.2.1)
+      activesupport (= 5.2.1)
       method_source
       rake (>= 0.8.7)
-      thor (>= 0.18.1, < 2.0)
+      thor (>= 0.19.0, < 2.0)
     rainbow (3.0.0)
     rake (12.3.1)
     rb-fsevent (0.10.3)
@@ -241,7 +248,7 @@ GEM
     therubyracer (0.12.3)
       libv8 (~> 3.16.14.15)
       ref
-    thor (0.20.0)
+    thor (0.20.3)
     thread_safe (0.3.6)
     tilt (2.0.8)
     tolk (2.0.0)
@@ -254,7 +261,7 @@ GEM
     unicode-display_width (1.4.0)
     uniform_notifier (1.11.0)
     websocket (1.2.8)
-    websocket-driver (0.6.5)
+    websocket-driver (0.7.0)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.3)
     will_paginate (3.1.6)
@@ -284,12 +291,12 @@ DEPENDENCIES
   listen
   minitest-stub-const
   mocha
-  mysql2 (~> 0.3.17)
+  mysql2 (~> 0.4.0)
   paperclip
   puma (~> 3.0)
   rack-dev-mark
   rack-mini-profiler
-  rails (~> 5.1.0)
+  rails (~> 5.2.1)
   rails-controller-testing
   rails-dom-testing (~> 2.0.0)
   rails_autolink
diff --git a/test/helpers/todo_helpers_test.rb b/test/helpers/todo_helpers_test.rb
index 6491b561..dceb6932 100644
--- a/test/helpers/todo_helpers_test.rb
+++ b/test/helpers/todo_helpers_test.rb
@@ -17,7 +17,7 @@ class TodosHelpersTest < ActionView::TestCase
     todo = todos(:call_bill_gates_every_day)
     predecessor = todos(:call_bill)
     html = remote_delete_dependency(todo, predecessor)
-    assert_equal "<a class=\"delete_dependency_button\" x_predecessors_id=\"1\" href=\"/todos/18/remove_predecessor\"><img title=\"Remove dependency (does not delete the action)\" align=\"absmiddle\" class=\"delete_item\" src=\"/images/blank.png\" alt=\"Blank\" /></a>", html
+    assert_equal "<a class=\"delete_dependency_button\" x_predecessors_id=\"1\" href=\"/todos/18/remove_predecessor\"><img title=\"Remove dependency (does not delete the action)\" align=\"absmiddle\" class=\"delete_item\" src=\"/images/blank.png\" /></a>", html
   end
 
   test "remote_promote_to_project_menu_item" do