diff --git a/lib/active_admin/devise.rb b/lib/active_admin/devise.rb
index <HASH>..<HASH> 100644
--- a/lib/active_admin/devise.rb
+++ b/lib/active_admin/devise.rb
@@ -36,7 +36,8 @@ module ActiveAdmin
       # Redirect to the default namespace on logout
       def root_path
         namespace = ActiveAdmin.application.default_namespace.presence
-        root_path_method = [*namespace, :root_path].join('_')
+        root_path_method = [namespace, :root_path].compact.join('_')
+
         url_helpers = Rails.application.routes.url_helpers
 
         path = if url_helpers.respond_to? root_path_method
diff --git a/spec/support/detect_rails_version.rb b/spec/support/detect_rails_version.rb
index <HASH>..<HASH> 100644
--- a/spec/support/detect_rails_version.rb
+++ b/spec/support/detect_rails_version.rb
@@ -6,9 +6,9 @@ unless defined? RAILS_VERSION_FILE
 end
 
 unless defined? TRAVIS_CONFIG
-  require 'psych'
+  require 'yaml'
   filename = File.expand_path("../../../.travis.yml", __FILE__)
-  TRAVIS_CONFIG = Psych.load File.read filename
+  TRAVIS_CONFIG = YAML.load_file filename
   TRAVIS_RAILS_VERSIONS = TRAVIS_CONFIG['env'].grep(/RAILS=(.*)/){ $1 }.sort
 end
Fixed support for Ruby <I>

* Ruby <I> does not support this * syntax. Using compact instead.
* Using the YAML constant instead of loading Psych directly. This
  ensures that it works in both Ruby <I> and <I>.