Save json data to file using AngularJS - json

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!