Send paperclip file via email as an attachment - Rails

I have a form that when a potential hire is interested in working for the company he/she fills it out and attaches a resume. The submission will go to a company representative with the attachment. The email is going through but the attachment is not the document and I cannot figure out how to configure it properly. In the submission email the attachment just says "document".

career_mailer.rb

class CareerMailer < ApplicationMailer

  default from: "[email protected]"



  def career_inquiry(career)
    @career = career
     attachments['attachment.extension'] = document
    mail(to: "[email protected]", subject: "This is just a test from Jay")
  end
end

career.rb (model)

class Career < ApplicationRecord

    has_attached_file :document

    validates_attachment_size :document, :less_than => 25.megabytes    
    validates_attachment_presence :document
     validates_attachment_content_type :document, :content_type => ["application/pdf","application/vnd.ms-excel",     
                                                                    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
                                                                    "application/msword", 
                                                                    "application/vnd.openxmlformats-officedocument.wordprocessingml.document", 
                                                                    "text/plain"]

    email_regex = /\A([\w+\-].?)+@[a-z\d\-]+(\.[a-z]+)*\.[a-z]+\z/i

    validates :name, :presence => true,
              :length          => { :maximum => 50 }
    validates :subject, :presence => true,
              :length          => { :maximum => 50 }
    validates :phone, :presence => true,
    :length          => { :maximum => 50 }
    validates :email, :presence => true,
              :format          => {:with => email_regex }
    validates :message, :presence => true,
              :length          => { :maximum => 5000 }

end

careers_controller.rb

class CareersController < ApplicationController
  def new
  @career = Career.new

  end
  def show
    @career = Career.find(params[:id])
  end 

  def create
    # fail
    @career = Career.create(career_params)
    if @career.save
      CareerMailer.career_inquiry(@career).deliver
      redirect_back(fallback_location: root_path)
    else
      flash[:error] = @career.errors.full_messages
      redirect_back(fallback_location: root_path)
    end


  end
  private
  def career_params
    params.require(:career).permit(:name, :phone, :subject, :email, :message, :document)
  end
end

UPDATE

I am trying the following in my career mailer:

attachments[career.document.attach_file_name] = File.read(career.document.attach.path)

I am getting the following error:

UPDATE 2

I am still working on this but I think based on everything I've read I need to pull the paperclip file before it saves to the model so I am going to figure out how to do so so I can send the uploaded resume as an attachment.