Odoo 9 product currency_id change
I'm trying to make each product should has own currency_id. e.g: Apple IPad's price 300$ for default, its price is dollar because my company currency. But i want to change dollar as euro and this can be each product like one is euro one is dollar one is try. In my custom module view.xml,
<record id="product_template_form_view_inherited" model="ir.ui.view">
<field name="inherit_id" ref="product.product_template_form_view" />
<field name="arch" type="xml">
<xpath expr="//notebook//page//group//group[@name='group_standard_price']" position="inside">
<field name="currency_id" readonly='0'/>
_inherit = 'product.template'
currency_id= fields.Many2one('res.currency',string='Currency',readOnly=False, store=True)
and this code works fine, i can select currency from drop down list and its changing product list_price currency. But when i try to save all changes its become again default company currency. How can i make this changes? Sorry about my english. If its not clear, i can send screenshots.