application_record.rb

class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true

  class << self
    # implements would take a list of modules and verify that the model "implementing"
    # defines the methods inside of the interface on itself
    def implements(*interfaces)
      interfaces_with_methods = interfaces.map do |interface|
        [interface.name, interface.instance_methods(false)]
      end

      interfaces_with_methods.each do |interface_name, interface_methods|
        verify_implements(interface_name, interface_methods)
      end
    end

    private

    def self_defined_methods
      @self_defined_methods ||= instance_methods(false)
    end

    def verify_implements(interface_name, interface_methods)
      interface_methods.each do |method_name|
        unless self_defined_methods.include?(method_name)
          raise NotImplementedError, "#{name} does not implement #{method_name} from #{interface_name}"
        end
      end
    end
  end
end

interface.rb

module Interface
  # Documentation on what `some_method` is used for, and what the implementation expects
  def method_to_implement; end
end

model.rb

class Model < ApplicationRecord
  # Will raise an error if the methods defined in Interface aren't implemented on Model
  implements Interface
  
  def method_to_implement
    # ...
  end
end