companies_controller.rb

def create
    #fail
    @company = Company.new(company_params)
    
    if @company.save
      flash[:notice] = "You have successfully created a new company"
      redirect_to(:action => 'index')
    else
      render('new')
    end
  end
  
  private
  
    def company_params
      params.require(:company).permit(:name, :company_number, :tax_number, :address, :city, :state, :zip, :telephone_number, :fax_number, :email_address, :website_address, :facebook_url, :twitter_username, :linkedin_url, :notes)
    end   

new_companies_controller.rb

def create
    #fail
    @company = Company.new(company_params)
    
    if @company.save
      flash[:notice] = "You have successfully created a new company"
      redirect_to(:action => 'index')
    else
      render('new')
    end
  end
  
  private
    
    # Now company_params returns a cleaned-up list of company attributes
    def company_params
      # this line is the same as before, I'm just storing this in a variable called dirty_params
      dirty_params = params.require(:company).permit(:name, :company_number, :tax_number, :address, :city, :state, :zip, :telephone_number, :fax_number, :email_address, :website_address, :facebook_url, :twitter_username, :linkedin_url, :notes)
      # Now, defer to another method that will clean up the parameters
      clean_params = remove_empty_strings(dirty_params)
      # Return the results
      return clean_params
    end   
    
    # This method has one job, can be called by the other actions in this controller if needed. Next step, move this out of the controller so it can be used all over the place. 
    def remove_empty_strings(params_that_need_cleaning)
      # Do something here to loop through your params and replace empty strings with nil
    end