diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b8380a4..5c1eecc 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
       CI: true
     strategy:
       matrix:
-        ruby-version: ['2.7', '3.0', '3.1', '3.2']
+        ruby-version: ['3.0', '3.1', '3.2']
     steps:
       - name: Checkout code
         uses: actions/checkout@v3
diff --git a/.gitignore b/.gitignore
index 9106b2a..ac66b17 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,5 @@
 /pkg/
 /spec/reports/
 /tmp/
+.byebug_history
+ignore.*
diff --git a/.rubocop.yml b/.rubocop.yml
index 81c0e1f..920bc72 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -2,4 +2,4 @@ inherit_gem:
   rubocop-espago: rubocop.yml
 
 AllCops:
-  TargetRubyVersion: 2.7
+  TargetRubyVersion: 3.0
diff --git a/Gemfile b/Gemfile
index c563c88..553f723 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,6 +5,7 @@ source 'https://rubygems.org'
 # Specify your gem's dependencies in diggable.gemspec
 gemspec
 
+gem 'byebug', '~> 11.1' # debugger
 gem 'minitest', '~> 5.0' # test framework
 gem 'rake', '~> 13.0' # automation tasks
 gem 'rubocop-espago', '~> 1.0' # ruby linter
diff --git a/Gemfile.lock b/Gemfile.lock
index 850cfd1..1d77d8b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -10,6 +10,7 @@ GEM
     ast (2.4.2)
     backport (1.2.0)
     benchmark (0.2.1)
+    byebug (11.1.3)
     diff-lcs (1.5.0)
     e2mmap (0.1.0)
     jaro_winkler (1.5.4)
@@ -77,6 +78,7 @@ PLATFORMS
   x86_64-linux
 
 DEPENDENCIES
+  byebug (~> 11.1)
   minitest (~> 5.0)
   rake (~> 13.0)
   rubocop-espago (~> 1.0)
diff --git a/README.md b/README.md
index 05b94db..92c5c36 100644
--- a/README.md
+++ b/README.md
@@ -90,7 +90,7 @@ class PaymentInstrument < Shale::Mapper
     attribute :expiration_month, ::Shale::Type::Integer
 end
 
-class Transaction < ::Shale::Mapper
+class Transaction < Shale::Mapper
     include Shale::Builder
 
     attribute :cvv_code, Shale::Type::String
@@ -142,6 +142,52 @@ non-primitive types have been overridden to accept blocks.
 When a block is given to such a getter, it instantiates an empty object
 of its type and yields it to the block.
 
+### Collections
+
+Whenever you call a getter with a block for a collection attribute, the built object will be appended to the array.
+
+Let's define a schema like this.
+
+```rb
+class Client < Shale::Mapper
+    include Shale::Builder
+
+    attribute :first_name, Shale::Type::String
+    attribute :last_name, Shale::Type::String
+    attribute :email, Shale::Type::String
+end
+
+class Transaction < Shale::Mapper
+    include Shale::Builder
+
+    attribute :clients, Client, collection: true
+end
+```
+
+You can easily build add new clients to the collection like so:
+
+```rb
+transaction = Transaction.build do |t|
+  # this will be added as the first element of the collection
+  t.clients do |c|
+    c.first_name = 'Foo'
+    c.last_name = 'Bar'
+  end
+
+  # this will be added as the second element of the collection
+  t.clients do |c|
+    c.first_name = 'Grant'
+    c.last_name = 'Taylor'
+  end
+end
+
+p transaction.clients
+# [
+#    #<Client:0x00000001066c2828 @first_name="Foo", @last_name="Bar", @email=nil>,
+#    #<Client:0x00000001066c24b8 @first_name="Grant", @last_name="Taylor", @email=nil>
+# ]
+```
+
 ### Conditional building
 
 This DSL makes it extremely easy to build nested
diff --git a/lib/shale/builder.rb b/lib/shale/builder.rb
index fa929eb..13d33dd 100644
--- a/lib/shale/builder.rb
+++ b/lib/shale/builder.rb
@@ -89,10 +89,25 @@ def build
       # @param name [String, Symbol]
       # @param type [Class]
       # @return [void]
-      def attribute(name, type, *args, **kwargs, &block)
+      def attribute(name, type, *args, collection: false, **kwargs, &block)
         super
         return unless type < ::Shale::Mapper
 
+        if collection
+          @builder_methods_module.class_eval <<~RUBY, __FILE__, __LINE__ + 1
+            def #{name}                           # def clients
+              return super unless block_given?    #   return super unless block_given?
+                                                  #
+              arr = self.#{name} ||= []           #   arr = self.clients ||= []
+              object = #{type}.new                #   object = Client.new
+              yield(object)                       #   yield(object)
+              arr << object                       #   arr << object
+              object                              #   object
+            end                                   # end
+          RUBY
+          return
+        end
+
         @builder_methods_module.class_eval <<~RUBY, __FILE__, __LINE__ + 1
           def #{name}                                   # def amount
             return super unless block_given?            #   return super unless block_given?
diff --git a/shale-builder.gemspec b/shale-builder.gemspec
index e7c96b7..a6dd973 100644
--- a/shale-builder.gemspec
+++ b/shale-builder.gemspec
@@ -12,7 +12,7 @@ Gem::Specification.new do |spec|
   spec.description = spec.summary
   spec.homepage = 'https://github.com/Verseth/ruby-shale-builder'
   spec.license = 'MIT'
-  spec.required_ruby_version = '>= 2.7.0'
+  spec.required_ruby_version = '>= 3.0.0'
 
   spec.metadata['homepage_uri'] = spec.homepage
   spec.metadata['source_code_uri'] = spec.homepage
diff --git a/test/shale/builder_test.rb b/test/shale/builder_test.rb
index 3002f9f..fc89ca8 100644
--- a/test/shale/builder_test.rb
+++ b/test/shale/builder_test.rb
@@ -41,6 +41,10 @@ class TestEnhancedTransactionType < TestTransactionType
     attribute :client_data, TestClientDataType
   end
 
+  class TestMultipleClientTransactionType < TestTransactionType
+    attribute :clients, TestClientDataType, collection: true
+  end
+
   context 'inheritance' do
     should 'correctly set up a class after inheriting' do
       mod_parent = TestTransactionType.builder_methods_module
@@ -152,6 +156,44 @@ class TestEnhancedTransactionType < TestTransactionType
     assert_equal 'USD', obj.amount.currency
   end
 
+  should 'build an object with a collection attribute' do
+    obj = TestMultipleClientTransactionType.build do |t|
+      t.cvv_code = '321'
+      t.amount do |a|
+        a.value = 45.0
+        a.currency = 'USD'
+      end
+      t.clients do |c|
+        c.first_name = 'Mateusz'
+        c.last_name = 'Gobbins'
+        c.email = 'mat.gobbins@example.com'
+      end
+      t.clients do |c|
+        c.first_name = 'Michal'
+        c.last_name = 'Zapow'
+        c.email = 'mich.zapow@example.com'
+      end
+    end
+
+    assert obj.is_a?(TestTransactionType)
+    assert_equal '321', obj.cvv_code
+    assert obj.amount.is_a?(TestAmountType)
+    assert_equal 45.0, obj.amount.value
+    assert_equal 'USD', obj.amount.currency
+    assert obj.clients.is_a?(::Array), "Should be and Array, got: #{obj.clients.class.inspect}"
+    assert_equal 2, obj.clients.length
+
+    cli = obj.clients.first
+    assert_equal 'Mateusz', cli.first_name
+    assert_equal 'Gobbins', cli.last_name
+    assert_equal 'mat.gobbins@example.com', cli.email
+
+    cli = obj.clients.last
+    assert_equal 'Michal', cli.first_name
+    assert_equal 'Zapow', cli.last_name
+    assert_equal 'mich.zapow@example.com', cli.email
+  end
+
   should 'build an object through the alt DSL' do
     obj = TestTransactionType.build do |t|
       t.cvv_code = '321'
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 30b756b..e3afacd 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -5,3 +5,4 @@
 
 require 'minitest/autorun'
 require 'shoulda-context'
+require 'byebug'