update database cleaner to work around failing spec

A transaction was used in the production code the spec covered. The issue is described here: https://github.com/DatabaseCleaner/database_cleaner/issues/234

Gemfile

@@ -144,11 +144,7 @@ group :test do
   gem 'factory_girl_rails', '~> 4.5'
   gem 'cucumber-rails', '~> 1.4.2', require: false
   gem 'rack_session_access'
-  # restrict because in version 1.3 a lot of tests using acts as journalized
-  # fail stating: "Column 'user_id' cannot be null". I don't understand the
-  # connection with database cleaner here but setting it to 1.2 fixes the
-  # issue.
-  gem 'database_cleaner', '~> 1.2.0'
+  gem 'database_cleaner', '~> 1.4.1'
   gem 'rspec', '~> 3.3.0'
   # also add to development group, so "spec" rake task gets loaded
   gem 'rspec-rails', '~> 3.3.0', group: :development

Gemfile.lock

@@ -161,7 +161,7 @@ GEM
       rails (>= 3, < 5)
     daemons (1.2.2)
     dalli (2.7.4)
-    database_cleaner (1.2.0)
+    database_cleaner (1.4.1)
     date_validator (0.7.1)
       activemodel
     debug_inspector (0.0.2)
@@ -491,7 +491,7 @@ DEPENDENCIES
   cucumber-rails (~> 1.4.2)
   daemons
   dalli (~> 2.7.2)
-  database_cleaner (~> 1.2.0)
+  database_cleaner (~> 1.4.1)
   date_validator (~> 0.7.1)
   delayed_job_active_record (~> 4.0.2)
   equivalent-xml (~> 0.5.1)