Why this is needed?

In Angular one checkbox <input type="checkbox" ng-model="..."> is linked with one model.
But in practice we usually want one model to store array of checked values from several checkboxes.
Checklist-model solves that task without additional code in controller.
You should play with attributes of <input type="checkbox"> tag:

1. set checklist-model instead of ng-model
2. set checklist-value - what should be picked as array item

Please, try out demos below:

Array of primitives

html

<label ng-repeat="role in roles">
  <input type="checkbox" checklist-model="user.roles" checklist-value="role"> {{role}}
</label>

js

var app = angular.module("app", ["checklist-model"]);
app.controller('Ctrl1', function($scope) {
  $scope.roles = [
    'guest', 
    'user', 
    'customer', 
    'admin'
  ];
  $scope.user = {
    roles: ['user']
  };
  $scope.checkAll = function() {
    $scope.user.roles = angular.copy($scope.roles);
  };
  $scope.uncheckAll = function() {
    $scope.user.roles = [];
  };
  $scope.checkFirst = function() {
    $scope.user.roles.splice(0, $scope.user.roles.length); 
    $scope.user.roles.push('guest');
  };
});

Array of objects (pick id)

html

<label ng-repeat="role in roles">
  <input type="checkbox" checklist-model="user.roles" checklist-value="role.id"> {{role.text}}
</label>

js

var app = angular.module("app", ["checklist-model"]);
app.controller('Ctrl2', function($scope) {
  $scope.roles = [
    {id: 1, text: 'guest'},
    {id: 2, text: 'user'},
    {id: 3, text: 'customer'},
    {id: 4, text: 'admin'}
  ];
  $scope.user = {
    roles: [2, 4]
  };
  $scope.checkAll = function() {
    $scope.user.roles = $scope.roles.map(function(item) { return item.id; });
  };
  $scope.uncheckAll = function() {
    $scope.user.roles = [];
  };
  $scope.checkFirst = function() {
    $scope.user.roles.splice(0, $scope.user.roles.length); 
    $scope.user.roles.push(1);
  };
});

Array of objects (pick object)

html

<label ng-repeat="role in roles">
  <input type="checkbox" checklist-model="user.roles" checklist-value="role"> {{role.text}}
</label>

js

var app = angular.module("app", ["checklist-model"]);
app.controller('Ctrl3', function($scope) {
  $scope.roles = [
    {id: 1, text: 'guest'},
    {id: 2, text: 'user'},
    {id: 3, text: 'customer'},
    {id: 4, text: 'admin'}
  ];
  $scope.user = {
    roles: [$scope.roles[1]]
  };
  $scope.checkAll = function() {
    $scope.user.roles = angular.copy($scope.roles);
  };
  $scope.uncheckAll = function() {
    $scope.user.roles = [];
  };
  $scope.checkFirst = function() {
    $scope.user.roles.splice(0, $scope.user.roles.length); 
    $scope.user.roles.push($scope.roles[0]);
  };
});

Object properties

html

<label ng-repeat="(key, text) in roles">
  <input type="checkbox" checklist-model="user.roles" checklist-value="key"> {{text}}
</label>

js

var app = angular.module("app", ["checklist-model"]);
app.controller('Ctrl4', function($scope) {
  $scope.roles = {
    g: 'Guest',
    u: 'User',
    c: 'Customer',
    a: 'Administrator'
  };
  $scope.user = {
    roles: ['c']
  };
  $scope.checkAll = function() {
    $scope.user.roles = Object.keys($scope.roles);
  };
  $scope.uncheckAll = function() {
    $scope.user.roles = [];
  };
  $scope.checkFirst = function() {
    $scope.user.roles.splice(0, $scope.user.roles.length); 
    $scope.user.roles.push('a');
  };
});