diff --git a/.travis.yml b/.travis.yml
index 1e319c35..c2b66fc9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,6 +12,7 @@ gemfile:
   - gemfiles/Gemfile-rails.5.1.x
   - gemfiles/Gemfile-rails.5.2.x
   - gemfiles/Gemfile-rails.6.0.x
+  - gemfiles/Gemfile-rails.6.1.x
   - gemfiles/Gemfile-rails.edge
 before_install:
   - gem install bundler -v '< 2'
@@ -26,14 +27,20 @@ matrix:
   exclude:
     - rvm: 2.2
       gemfile: gemfiles/Gemfile-rails.6.0.x
+    - rvm: 2.2
+      gemfile: gemfiles/Gemfile-rails.6.1.x
     - rvm: 2.2
       gemfile: gemfiles/Gemfile-rails.edge
     - rvm: 2.3
       gemfile: gemfiles/Gemfile-rails.6.0.x
+    - rvm: 2.3
+      gemfile: gemfiles/Gemfile-rails.6.1.x
     - rvm: 2.3
       gemfile: gemfiles/Gemfile-rails.edge
     - rvm: 2.4
       gemfile: gemfiles/Gemfile-rails.6.0.x
+    - rvm: 2.4
+      gemfile: gemfiles/Gemfile-rails.6.1.x
     - rvm: 2.4
       gemfile: gemfiles/Gemfile-rails.edge
 cache: bundler
diff --git a/Gemfile b/Gemfile
index 4d0f5549..8bedd344 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,19 +6,20 @@ if ENV["edge"]
   gem "activerecord", :github => "rails/rails"
 end
 
+
+group :development, :test do
+  gem 'minitest', '~> 5.14.0'
+end
+
 group :development do
-  gem 'minitest', '5.10.1'
   gem 'mocha'
   gem "rake"
   gem "yard"
 
-  platforms :ruby_21 do
-    gem "activerecord", "< 5.0"
-    gem "activesupport", "< 5.0"
-  end
-
   platforms :ruby do
-    gem "sqlite3"
+    gem "activerecord", "< 7.0"
+    gem "activesupport", "< 7.0"
+    gem "sqlite3", '~> 1.4'
     gem "redcarpet"
 
     if RUBY_VERSION > "2.1.0"
@@ -30,8 +31,4 @@ group :development do
     gem "activerecord-jdbcsqlite3-adapter"
     gem "jruby-openssl", :require => false # Silence openssl warnings.
   end
-end
-
-group :test do
-  gem 'minitest', '5.10.1'
-end
+end
\ No newline at end of file
diff --git a/gemfiles/Gemfile-rails.6.1.x b/gemfiles/Gemfile-rails.6.1.x
new file mode 100644
index 00000000..f686f7bc
--- /dev/null
+++ b/gemfiles/Gemfile-rails.6.1.x
@@ -0,0 +1,21 @@
+source "http://rubygems.org"
+
+gemspec :path => ".."
+
+gem "activerecord", "~> 6.1.1"
+
+group :development do
+  gem 'mocha'
+  gem "rake"
+  gem "yard"
+
+  platforms :ruby do
+    gem "sqlite3", '~> 1.4'
+    gem "redcarpet"
+  end
+
+  platforms :jruby do
+    gem "activerecord-jdbcsqlite3-adapter"
+    gem "jruby-openssl", :require => false # Silence openssl warnings.
+  end
+end
diff --git a/lib/rails_erd/domain.rb b/lib/rails_erd/domain.rb
index f292409b..bf836b89 100644
--- a/lib/rails_erd/domain.rb
+++ b/lib/rails_erd/domain.rb
@@ -49,7 +49,13 @@ def initialize(models = [], options = {})
     # Returns the domain model name, which is the name of your Rails
     # application or +nil+ outside of Rails.
     def name
-      defined? Rails and Rails.application and Rails.application.class.parent.name
+      return unless defined?(Rails) && Rails.application
+
+      if Rails.application.class.respond_to?(:module_parent)
+        Rails.application.class.module_parent.name
+      else
+        Rails.application.class.parent.name
+      end
     end
 
     # Returns all entities of your domain model.
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 2febc6db..ff664526 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -16,6 +16,14 @@
   ActiveSupport::TestCase.test_order = :random
 end
 
+# Patch to make Rails 6.1 work.
+module Kernel
+  # class_eval on an object acts like singleton_class.class_eval.
+  def class_eval(*args, &block)
+    singleton_class.class_eval(*args, &block)
+  end
+end
+
 class ActiveSupport::TestCase
   include RailsERD
 
@@ -171,6 +179,11 @@ def name_to_object_symbol_pairs(name)
 
     parts[1..-1].inject([[Object, parts.first.to_sym]]) do |pairs,string|
       last_parent, last_child = pairs.last
+      # Fixes for Rails 6. No idea if this is actually correct as I can't decipher what the heck is going on in this
+      # code.
+      if last_child == :ActiveRecord || last_child == :primary
+        break []
+      end
 
       break pairs unless last_parent.const_defined?(last_child)
 
diff --git a/test/unit/attribute_test.rb b/test/unit/attribute_test.rb
index f4f51404..f7d98a76 100644
--- a/test/unit/attribute_test.rb
+++ b/test/unit/attribute_test.rb
@@ -3,9 +3,9 @@
 
 class AttributeTest < ActiveSupport::TestCase
   def with_native_limit(type, new_limit)
-    ActiveRecord::Base.connection.class_eval do
+    ActiveRecord::Base.connection.singleton_class.class_eval do
       undef :native_database_types
-      define_method :native_database_types do
+      define_method(:native_database_types) do
         super().tap do |types|
           types[type][:limit] = new_limit
         end
@@ -13,9 +13,9 @@ def with_native_limit(type, new_limit)
     end
     yield
   ensure
-    ActiveRecord::Base.connection.class_eval do
+    ActiveRecord::Base.connection.singleton_class.class_eval do
       undef :native_database_types
-      define_method :native_database_types do
+      define_method(:native_database_types) do
         super()
       end
     end
@@ -266,14 +266,14 @@ def create_attribute(model, name)
   end
 
   test "limit should return nil for oddball column types that misuse the limit attribute" do
-    create_model "Business", :location => :integer
-    attribute = create_attribute(Business, "location")
-    attribute.column.class_eval do
-      define_method :limit do
+    create_model "Business", :location => :integer do
+      define_singleton_method :limit do
         # https://github.com/voormedia/rails-erd/issues/21
         { :srid => 4326, :type => "point", :geographic => true }
       end
     end
+
+    attribute = create_attribute(Business, "location")
     assert_nil attribute.limit
   end
 
@@ -306,13 +306,12 @@ def create_attribute(model, name)
   end
 
   test "scale should return nil for oddball column types that misuse the scale attribute" do
-    create_model "Kobold", :size => :integer
-    attribute = create_attribute(Kobold, "size")
-    attribute.column.class_eval do
+    create_model "Kobold", :size => :integer do
       define_method :scale do
         1..5
       end
     end
+    attribute = create_attribute(Kobold, "size")
     assert_nil attribute.scale
   end
 end