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diff --git a/lib/declarative_enum.rb b/lib/declarative_enum.rb
new file mode 100644
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+++ b/lib/declarative_enum.rb
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+# frozen_string_literal: true
+
+# Extending this module will give you the ability of defining
+# enum values in a declarative way.
+#
+#   module DismissalReasons
+#     extend DeclarativeEnum
+#
+#     key  :dismissal_reason
+#     name 'DismissalReasonOfVulnerability'
+#
+#     description <<~TEXT
+#       This enum holds the user selected dismissal reason
+#       when they are dismissing the vulnerabilities
+#     TEXT
+#
+#     define do
+#       acceptable_risk value: 0, description: 'The vulnerability is known but is considered to be an acceptable business risk.'
+#       false_positive value: 1, description: 'An error in reporting the presence of a vulnerability in a system when the vulnerability is not present.'
+#       used_in_tests value: 2, description: 'The finding is not a vulnerability because it is part of a test or is test data.'
+#     end
+#
+# Then we can use this module to register enums for our Active Record models like so,
+#
+#   class VulnerabilityFeedback
+#     declarative_enum DismissalReasons
+#   end
+#
+# Also we can use this module to create GraphQL Enum types like so,
+#
+# module Types
+#   module Vulnerabilities
+#     class DismissalReasonEnum < BaseEnum
+#       declarative_enum DismissalReasons
+#     end
+#   end
+# end
+#
+# rubocop:disable Gitlab/ModuleWithInstanceVariables
+module DeclarativeEnum
+  # This `prepended` hook will merge the enum definition
+  # of the prepended module into the base module to be
+  # used by `prepend_if_ee` helper method.
+  def prepended(base)
+    base.definition.merge!(definition)
+  end
+
+  def key(new_key = nil)
+    @key = new_key if new_key
+
+    @key
+  end
+
+  def name(new_name = nil)
+    @name = new_name if new_name
+
+    @name
+  end
+
+  def description(new_description = nil)
+    @description = new_description if new_description
+
+    @description
+  end
+
+  def define(&block)
+    raise LocalJumpError.new('No block given') unless block
+
+    @definition = Builder.new(definition, block).build
+  end
+
+  # We can use this method later to apply some sanity checks
+  # but for now, returning a Hash without any check is enough.
+  def definition
+    @definition.to_h
+  end
+
+  class Builder
+    KeyCollisionError = Class.new(StandardError)
+
+    def initialize(definition, block)
+      @definition = definition
+      @block = block
+    end
+
+    def build
+      instance_exec(&@block)
+
+      @definition
+    end
+
+    private
+
+    def method_missing(name, *arguments, value: nil, description: nil, &block)
+      key = name.downcase.to_sym
+      raise KeyCollisionError, "'#{key}' collides with an existing enum key!" if @definition[key]
+
+      @definition[key] = {
+        value: value,
+        description: description
+      }
+    end
+  end
+end
+# rubocop:enable Gitlab/ModuleWithInstanceVariables