Save json data to file using AngularJS

Question

I'm new to AngularJs. I'm having some trouble with this task.

I have the json file:

[{
    "day": {"date": "12.01.2015", "dow": "monday", "in":"1"},
    "lessons": [
        {"time": "9.45 – 12.35", "title": "title", "teacher": "tname", "room": "3"},          
        ... more lessons ...            
    ]
}, 
... more days ... 
]

My html file:

<table style="width: 100%;" class="table table-bordered">
        <tbody ng-repeat="timetable in timetables" ng-if="ind==-1||ind==$index">
            <tr ng-repeat="lesson in timetable.lessons">
                <td rowspan="{{timetable.lessons.length}}" ng-if="!$index" style="vertical-align: top; text-align: left;">
                    {{timetable.day.date}}<br />
                    <div style="width: 100%; height: 100%; min-height: 100%; ">
                        <a href="#/list/{{timetable.day.in - 1}}" > {{timetable.day.dow}}</a></div>
                </td>
                <td>{{lesson.time}}</td>
                <td>{{lesson.title}}</td>
                <td>{{lesson.teacher}} <input type="textbox" ng-model="lesson.teacher"/></td>

                <td>{{lesson.room}}</td>
            </tr>
        </tbody>        
    </table>

controllers.js:

angular.module('schedule.controllers', [])
    .controller('ListLessonsCtrl', ['$scope', 'Schedule' , "$routeParams",
        function ($scope, Schedule, $routeParams) {
            if ($routeParams.ind === undefined) {
                $scope.ind = -1;
            } else {
                $scope.ind = $routeParams.ind;
            }
            $scope.timetables = Schedule.query(); // get data form json file

            $scope.save = function() {
                Schedule.save($scope.timetables); // not works properly
            };
        }
    ])
... more code ...

And, finally, my services.js file:

angular.module('schedule.services', ['ngResource'])
.factory('Schedule', ['$resource', function($resource) {
    return $resource('schedule/schedule.json', {}, {
        query: {method: 'GET', isArray: true},
        save: {method: 'POST'}
    });
}]);

I need to get data from json file (done), update it on the page (know how to do it), and save updated data back to json file.

I tried to add function "save" to existing factory, but I don't know exactly, how to send data to it.

Could someone help me with it?

Thanks in advance!