new.html.erb

<%= form_tag registration_index_path do %>
  <%= fields_for User.new do |u| %>
    <%= u.label :phone %>
    <%= u.text_field :phone %>
  <% end %>
  <p>
    <%= label_tag :workout %>
    <%= check_box_tag :workout %>
  </p>
  <p>
    <%= label_tag :quote %>
    <%= check_box_tag :quote %>
  </p>
  <p>
    <%= label_tag :tip %>
    <%= check_box_tag :tip %>
  </p>

  <%= fields_for Reminder.new do |r| %>
    <p>
      <%= r.label :monday %>
      <%= r.check_box :monday %>
    </p>
    <p>
      <%= r.label :tuesday %>
      <%= r.check_box :tuesday %>
    </p>
    <p>
      <%= r.label :wednesday %>
      <%= r.check_box :wednesday %>
    </p>
    <p>
      <%= r.label :thursday %>
      <%= r.check_box :thursday %>
    </p>
    <p>
      <%= r.label :friday %>
      <%= r.check_box :friday %>
    </p>
    <p>
      <%= r.label :saturday %>
      <%= r.check_box :saturday %>
    </p>
    <p>
      <%= r.label :sunday %>
      <%= r.check_box :sunday %>
    </p>
    <p>
      <%= r.label :send_at %>
      <%= r.time_select :send_at %>
    </p>

    <p>
      <%= r.label :time_zone %>
      <%= r.time_zone_select :time_zone, ActiveSupport::TimeZone.us_zones %>
    </p>
  <% end %>

  <%= submit_tag :submit %>
<% end %>

registration_controller.rb

class RegistrationController < ApplicationController
  before_filter :find_user

  def create
    if @user.save
      add_reminders_to @user
    else
      render :new, :errors => "Something weird"
    end
  end

  private 

  def find_user
    @user = User.find_or_create_by_phone(params[:user][:phone])
    @user.save! if @user.new_record?
  end

  def add_reminders_to( user )
    ## update user
    # Ensure they have selected a notification type
    # all is scoped to return workout, quotes and tips in order, first grabs the first.
    if params[:workout] 
      @reminder = user.reminders.build( Workout.all.first.reminders.build( params[:reminder] ).attributes )
      if @reminder.save
        redirect_to congrats_path
      else
        render :new, :error => "There was some validation error"
      end
    end

    if params[:quote]
      @quote = user.reminders.build( Quote.all.first.reminders.build( params[:reminder] ).attributes )
      if @quote.save
        redirect_to congrats_path
      else
        render :new, :error => "There was some validation error"
      end
    end

    if params[:tip]
      redirect_to congrats_path
    end

    if !params[:tip] and !params[:quote] and !params[:workout]
      render :new, :errors => "you must add a workout, tip or quote."
    end

  end
end