1.form.html.haml

/ Form excerpt
= f.button t(".save"), class: "btn"
= f.button t(".publish"), class: "btn", name: "publish"
= f.button t(".test"), class: "btn", name: "test"

2.routes.rb

class MultibuttonFormConstraint
  def initialize(button_name)
    @button_name = button_name
  end

  def matches?(request)
    request.params.key? @button_name
  end
end


# Add new routes with appropriate constrains
resources :subscriptions do
  patch '' => "subscriptions#publish", on: :member, constraints: MultibuttonFormConstraint.new(:publish)
  patch '' => "subscriptions#test", on: :member, constraints: MultibuttonFormConstraint.new(:test)
end

3.subscriptions_controller.rb

class SubscriptionController < ApplicationController
  # CRUD
  
  def update
    # process REST update
  end
  
  def publish
    # process publish action
  end
  
  def test
    # process test action
  end
  
  # ...

end