Retrieving records in ember js

I'm new to ember js. I have a form & when a user hit submit i want to check whether the username & password that user have entered, is already in my model/database.I tried following,But it didn't work. Please help me with this...

Template

<h2>Welcome to my blog</h2>

 <form {{action 'exist' on="submit"}}>

        <dl>
        <dt>User Name:<br> {{textarea value=uName cols="20" rows="1"}}</dt>
        <dt>Password:<br> {{textarea value=passw cols="20" rows="1"}}</dt>
        </dl>
        <button type="submit" class="btn btn-primary">Login</button>
 </form>

Model

import DS from 'ember-data';

export default DS.Model.extend({

    FirstName: DS.attr('string'),
    UserName: DS.attr('string'),
    Password: DS.attr('string'),
    PermissionList: DS.attr('array')

});

Route

import Ember from 'ember';

export default Ember.Route.extend({
    model: function() {
        return this.store.find('user');
    }
});

Controller

import Ember from 'ember';

export default Ember.Controller.extend({


 actions: {  
        ght: function() {


        var uName = this.get('uName');
        var passw = this.get('passw');

        if(this.store.find('user',{userName:this.get('uName')} ))
        {
        alert('Already exist');
        }


                }
  }

});

// This alert is shown for every input.Even they are not in the model