Cannot POST data - Ionic Framework

I have created a small application in which i am posting just one field name district in database using php mysql - my app.js file has code -

angular.module('todo', ['ionic'])
.controller('TodoCtrl', function($scope,$http) {
$scope.insertdata = function(){
console.log($scope.district);
$http.post('insert.php',{'district':$scope.district})
.success(function(data)
{
console.log("Done");
})
} });

and index.html has

<body ng-app="todo" ng-controller="TodoCtrl">
<form>
<input type="text" ng-model="district"/>
<input type="button" value="submit" ng-click="insertdata()"/>
</form>

and insert.php has:

$data = json_decode(file_get_contents("php://input"));
$districtname = mysql_escape_string($data->district);
mysql_connect("localhost","root","");
mysql_select_db("test");
mysql_query("Insert into districtapp (districtname) Values ('".$districtname."')");

I have installed codova whitelist and added these lines :

<access origin="*"/>
<allow-navigation href="http://*/*" />
<allow-navigation href="https://*/*" />
<allow-navigation href="data:*" />

I run app by ionic serve and get :

Error : POST http://192.168.2.152:8100/insert.php 404 Not Found

Can anyone please help me to solve this Posting issue?