diff --git a/.rubocop.yml b/.rubocop.yml
index 5fa131f..f6bb2ef 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,4 +1,5 @@
-require: rubocop-performance
+require:
+  - rubocop-performance
 
 Rails:
   Enabled: true
diff --git a/.travis.yml b/.travis.yml
index 5a826f2..4d2a924 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,18 +1,33 @@
 language: ruby
+dist: xenial
 
 rvm:
-  - 2.5.3
-  - 2.4.5
-  - 2.3.8
+  - 2.6.3
+  - 2.5.5
+  - 2.4.6
+
+services:
+  - mysql
+  - postgresql
 
 env:
   - REDMINE_VER=4.0-stable DB=postgresql
   - REDMINE_VER=3.4-stable DB=postgresql
+  - REDMINE_VER=4.0-stable DB=mysql
+  - REDMINE_VER=3.4-stable DB=mysql
 
 sudo: true
 
-addons:
-  postgresql: "9.6"
+matrix:
+  exclude:
+  - rvm: 2.6.3
+    env: REDMINE_VER=3.4-stable DB=mysql
+  - rvm: 2.6.3
+    env: REDMINE_VER=3.4-stable DB=postgresql
+  - rvm: 2.5.5
+    env: REDMINE_VER=3.4-stable DB=mysql
+  - rvm: 2.5.5
+    env: REDMINE_VER=3.4-stable DB=postgresql
 
 notifications:
   webhooks:
@@ -26,6 +41,7 @@ before_install:
   - export REDMINE_GIT_REPO=git://github.com/redmine/redmine.git
   - export REDMINE_PATH=$HOME/redmine
   - export BUNDLE_GEMFILE=$REDMINE_PATH/Gemfile
+  - export RAILS_ENV=test
   - git clone $REDMINE_GIT_REPO $REDMINE_PATH
   - cd $REDMINE_PATH
   - if [[ "$REDMINE_VER" != "master" ]]; then git checkout -b $REDMINE_VER origin/$REDMINE_VER; fi
@@ -34,12 +50,7 @@ before_install:
   - cp $TRAVIS_BUILD_DIR/test/support/database-$DB-travis.yml $REDMINE_PATH/config/database.yml
 
 before_script:
-  # - bundle exec rake redmine:load_default_data REDMINE_LANG=en
-  # - bundle exec rake db:structure:dump
-  - psql -c 'create database travis_ci_test;' -U postgres
-  # - bundle exec rake db:create
-  - bundle exec rake db:migrate
-  - bundle exec rake redmine:plugins:migrate
+  - bundle exec rake db:create db:migrate redmine:plugins:migrate
 
 script:
   - export SKIP_COVERAGE=1
diff --git a/CHANGELOG.md b/CHANGELOG.md
index aea29fb..e8e2408 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,7 @@ Changelog
 1.0.5
 -----
 
-- ruby 2.3.x or newer is required
+- ruby 2.4.x or newer is required
 
 
 1.0.4
diff --git a/Gemfile b/Gemfile
index e7117a8..cd397d6 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,2 +1,8 @@
 gem 'slim-rails'
 gem 'validate_url'
+
+group :development, :test do
+  gem 'brakeman', require: false
+  gem 'rubocop', require: false
+  gem 'rubocop-performance', require: false
+end
diff --git a/README.md b/README.md
index df38ce9..bf9d036 100644
--- a/README.md
+++ b/README.md
@@ -57,7 +57,7 @@ Requirements
 ------------
 
 * Redmine version >= 3.0.0
-* Ruby version >= 2.3.0
+* Ruby version >= 2.4.0
 
 
 Installation
diff --git a/init.rb b/init.rb
index 5c215ae..71d20e2 100644
--- a/init.rb
+++ b/init.rb
@@ -1,7 +1,6 @@
 raise "\n\033[31mredmine_messenger requires ruby 2.3 or newer. Please update your ruby version.\033[0m" if RUBY_VERSION < '2.3'
 
-require 'redmine'
-require 'redmine_messenger'
+require_dependency 'redmine_messenger'
 
 Redmine::Plugin.register :redmine_messenger do
   name 'Redmine Messenger'
@@ -41,3 +40,13 @@ Redmine::Plugin.register :redmine_messenger do
     post_password_updates: '0'
   }, partial: 'settings/messenger_settings'
 end
+
+begin
+  if ActiveRecord::Base.connection.table_exists?(Setting.table_name)
+    Rails.configuration.to_prepare do
+      RedmineMessenger.setup
+    end
+  end
+rescue ActiveRecord::NoDatabaseError
+  Rails.logger.error 'database not created yet'
+end
diff --git a/lib/redmine_messenger.rb b/lib/redmine_messenger.rb
index 32e1869..2476a13 100644
--- a/lib/redmine_messenger.rb
+++ b/lib/redmine_messenger.rb
@@ -1,11 +1,27 @@
-Rails.configuration.to_prepare do
-  module RedmineMessenger
-    REDMINE_CONTACTS_SUPPORT = Redmine::Plugin.installed?('redmine_contacts') ? true : false
-    REDMINE_DB_SUPPORT = Redmine::Plugin.installed?('redmine_db') ? true : false
-    # this does not work at the moment, because redmine loads passwords after messener plugin
-    REDMINE_PASSWORDS_SUPPORT = Redmine::Plugin.installed?('redmine_passwords') ? true : false
+module RedmineMessenger
+  REDMINE_CONTACTS_SUPPORT = Redmine::Plugin.installed?('redmine_contacts') ? true : false
+  REDMINE_DB_SUPPORT = Redmine::Plugin.installed?('redmine_db') ? true : false
+  # this does not work at the moment, because redmine loads passwords after messener plugin
+  REDMINE_PASSWORDS_SUPPORT = Redmine::Plugin.installed?('redmine_passwords') ? true : false
 
-    def self.settings
+  class << self
+    def setup
+      # Patches
+      Issue.send(:include, RedmineMessenger::Patches::IssuePatch)
+      WikiPage.send(:include, RedmineMessenger::Patches::WikiPagePatch)
+      ProjectsController.send :helper, MessengerProjectsHelper
+      Contact.send(:include, RedmineMessenger::Patches::ContactPatch) if RedmineMessenger::REDMINE_CONTACTS_SUPPORT
+      DbEntry.send(:include, RedmineMessenger::Patches::DbEntryPatch) if RedmineMessenger::REDMINE_DB_SUPPORT
+      Password.send(:include, RedmineMessenger::Patches::PasswordPatch) if Redmine::Plugin.installed?('redmine_passwords')
+
+      # Global helpers
+      ActionView::Base.send :include, RedmineMessenger::Helpers
+
+      # Hooks
+      require_dependency 'redmine_messenger/hooks'
+    end
+
+    def settings
       if Setting[:plugin_redmine_messenger].class == Hash
         if Rails.version >= '5.2'
           # convert Rails 4 data
@@ -21,24 +37,10 @@ Rails.configuration.to_prepare do
       end
     end
 
-    def self.setting?(value)
+    def setting?(value)
       return true if settings[value].to_i == 1
 
       false
     end
   end
-
-  # Patches
-  Issue.send(:include, RedmineMessenger::Patches::IssuePatch)
-  WikiPage.send(:include, RedmineMessenger::Patches::WikiPagePatch)
-  ProjectsController.send :helper, MessengerProjectsHelper
-  Contact.send(:include, RedmineMessenger::Patches::ContactPatch) if RedmineMessenger::REDMINE_CONTACTS_SUPPORT
-  DbEntry.send(:include, RedmineMessenger::Patches::DbEntryPatch) if RedmineMessenger::REDMINE_DB_SUPPORT
-  Password.send(:include, RedmineMessenger::Patches::PasswordPatch) if Redmine::Plugin.installed?('redmine_passwords')
-
-  # Global helpers
-  ActionView::Base.send :include, RedmineMessenger::Helpers
-
-  # Hooks
-  require_dependency 'redmine_messenger/hooks'
 end
diff --git a/test/support/database-mysql-travis.yml b/test/support/database-mysql-travis.yml
new file mode 100644
index 0000000..2acc077
--- /dev/null
+++ b/test/support/database-mysql-travis.yml
@@ -0,0 +1,8 @@
+test:
+  adapter: mysql2
+  database: travis_ci_test
+  host: localhost
+  username: root
+  password:
+  pool: 5
+  encoding: utf8mb4