I am not able to find the addon created inspite of restarting the server and updating the module list. Here is my code
__init__.py
import lead_assign
__openerp__.py
{
    'name' : "Assigning Leads",
    'version' : "1.0",
    'author' : "Nupur",
    'category' : "Tools",
    'depends' : ['base','crm'],
    'update_xml' : [
        'lead_assign.xml'
    ],
    'data' : []
    'demo' : [
    ],
    'installable': True,
}
lead_assign.py
from openerp.osv import osv
from openerp.osv import fields
class idea_idea(osv.osv):
          _inherit = 'crm.lead'
          _columns = {
            'user_id' : fields.many2one('res.users','Salesperson')
          }
idea_idea()
lead_assign.xml
<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <record id="view_assign_lead1_form" model="ir.ui.view"/>
            <field name="name">salesperson_form</field>
            <field name="model">res.users</field>
            <field name="type">form</field>
            <field name="arch" type="xml">
                <form string="Assign Leads">
                    <separator colspan="4" string="Do you really want to assign leads)?"/> 
                    <group>
                        <field name="user_id"/>
                    </group> 
                    <footer> 
                        <button name="assign_lead" string="Assign Leads" type="object" class="oe_highlight"/> or <button string="Cancel" class="oe_link" special="cancel"/> 
                    </footer> 
                </form>
            </field>
        </record>
        <record model="ir.actions.act_window" id="base.action_assign_lead_1">
            <field name="name">Assign Lead1</field>
            <field name="domain">[('id','in',active_ids)]</field>
            <field name="context">{"context dictionary (max 250 characters)"}</field>
            <field name="res_model">crm.lead</field>
            <field name="view_id">salesperson_form</field>
            <field name="view_type">form</field>
            <field name="view_mode">form,tree|tree,form|form|tree</field>
            <field name="target">new</field>
        </record>
        <record id="base.values_view_form_action" model="ir.values">
            <field name="name">Assign Lead1</field>
            <field name="action_id" ref="Assign Lead1"/>
            <field name="value_unpickle" eval="'ir.actions.act_window,' +ref('id_for_the_action"/>
            <field name="key">action</field>
            <field name="model_id" ref="crm.lead"/>
            <field name="model">crm.lead</field>
            <field name="key2">client_action_multi</field>
        </record>
    </data>
</openerp>
