How to use the ember-cli-mirage.Model.extend function in ember-cli-mirage

import { Model } from 'ember-cli-mirage';

export default Model.extend();

import { Model, belongsTo } from 'ember-cli-mirage';

export default Model.extend({
  category: belongsTo(),
  user: belongsTo()
});

import { Model, belongsTo } from 'ember-cli-mirage';

export default Model.extend({
  proposal: belongsTo(),
  author: belongsTo('participant')
});

import { Model, belongsTo } from 'ember-cli-mirage';

export default Model.extend({
  role: belongsTo(),
  user: belongsTo()
});

import { Model, belongsTo } from 'ember-cli-mirage';

export default Model.extend({
  task: belongsTo(),
  user: belongsTo()
});

import { Model, belongsTo, hasMany } from 'ember-cli-mirage';

export default Model.extend({
  donationGoals: hasMany('donation-goal'),
  githubRepos: hasMany('github-repo'),
  organization: belongsTo(),
  projectCategories: hasMany('project-category'),
  projectSkills: hasMany('project-skill'),
  projectUsers: hasMany('project-user'),
  stripeConnectPlan: belongsTo('stripe-connect-plan'),
  taskLists: hasMany('task-list'),
  tasks: hasMany()
});

import { Model } from 'ember-cli-mirage';

export default Model.extend({});

import { Model } from 'ember-cli-mirage';

export default Model.extend({});

import { Model, belongsTo, hasMany } from 'ember-cli-mirage';

export default Model.extend({
  repository: belongsTo('repository'),
  commit: belongsTo('commit', { inverseOf: 'build' }),
  branch: belongsTo('branch', { inverseOf: 'builds' }),
  jobs: hasMany('job'),
  stages: hasMany('stage'),
});

import { Model, belongsTo } from 'ember-cli-mirage';

export default Model.extend({
  githubAppInstallation: belongsTo('github-app-installation'),
  project: belongsTo('project')
});