Set Rails date format for view - ruby-on-rails

Question

What's the most efficient way to display a date in a view in dd/mm/yyyy format?
I modified config/initializers/date_time.rb as such:
# Date
Date::DATE_FORMATS[:default] = "%d/%m/%Y"
However, I have a dropdown list that contains dates, and I use that to pass a date parameter date_id for searching purpose. If I use the above line, it doesn't return any results when it should.
My code:
balances_controller.rb
def statement
#dates = Balance.select("distinct(date)").order('date desc')
if (params[:date_id].blank?)
#latestDate = Balance.order('date desc').first.date
else
#latestDate = params[:date_id]
end
#summaryBalances = Balance.joins(:account).order('accounts.credit').where('date = :abc', {abc: #latestDate})
end
statement.html.erb
<h1>Statement at <%= #latestDate %></h1>
<%= form_tag("/statement", method: "get") do %>
<%= select_tag "date_id", options_for_select( #dates.collect {|d| [ d.date, d.date ] }) %>
<%= submit_tag("Search") %>
<% end %>
<div class="table-responsive">
<table class="table">
<thead>
<tr>
<th>Account</th>
<th>Balance</th>
<th colspan="1"></th>
</tr>
</thead>
<tbody>
<% #summaryBalances.each do |balance| %>
<tr>
<td><%= balance.account.name %></td>
<td class='account-balance'><%= number_to_currency(balance.balance, unit: "£") %></td>
<td><%= link_to 'Edit', edit_balance_path(balance) %></td>
</tr>
<% end %>
</tbody>
</table>
</div>
UPDATE:
html output:
<form action="/statement" accept-charset="UTF-8" method="get"><input name="utf8" type="hidden" value="✓" />
<select name="date_id" id="date_id"><option value="2015-11-30">30/11/2015</option>
<option value="2015-10-31">31/10/2015</option>
<option value="2015-09-30">30/09/2015</option></select>
<input type="submit" name="commit" value="Search" />
</form>
I'm not sure if this is the most efficient way of resolving this but I've managed to do what I need it to do by creating two separate helper methods. One to display the date in dd/mm/yyyy format and one to return the date in yyyy-mm-dd format for the parameter.
def date_format(date)
date.to_date.strftime("%d/%m/%Y")
end
def date_format2(date)
date.to_date.strftime("%Y-%m-%d")
end
Updated statement.html.erb
....
<%= form_tag("/statement", method: "get") do %>
<%= select_tag "date_id", options_for_select( #dates.collect {|d| [ date_format(d.date), date_format2(d.date) ] }) %>
<%= submit_tag("Search") %>
<% end %>
....