new.html.erb

<h2>New Portfolio</h2>

<%= form_for @portfolio do |f| %>
  <%= render 'shared/error_messages', :object => @portfolio %>
  <div class="field" style="padding-top: 20px;">
    <%= f.label :name %><br />
    <%= f.text_field :name %>
  </div>
  <div class="field" style="padding-top: 20px;">
    <%= f.label :beginning_cash_balance %><br />
    <%= collection_select(:portfolio, :base_currency, Currency.all, :id, :description,
                          :selected => @portfolio.base_currency.id) %>
    <%= f.text_field :cash, :value => number_with_precision(@portfolio.cash, :precision => 2) %>
  </div>
  <div class="field small">
    <%= f.label :private %>
    <%= f.check_box :private %>
    <i>(Note, public portfolios only show percentages, not actual amounts)</i>
  </div>
  <div class="actions">
    <%= f.submit "Create" %>
  </div>
<% end -%>

portfolio.rb

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  def set_defaults
    self.name ||= "Portfolio #{user.portfolios.count + 1}"
    self.base_currency ||= Currency.find_by_code("USD")
  end
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portfolios_controller.rb

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  # GET /portfolios/new[.format]
  def new
    @portfolio = @user.portfolios.build
    @portfolio.set_defaults
  end

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