auth.js

//app/sessions/application
import Session from 'simple-auth/session';
import Ember from 'ember';
const { computed } = Ember;
const { service } = Ember.inject;

export default Session.extend({
  store: service(),
  user: computed('secure.userId', function(){
    return this.get('store').findRecord('user', this.get('secure.userId'));
  })
});

//config/environment.js
'simple-auth': {
  session: 'session:application'
}

this gave me an error:

Uncaught Error: Attempting to inject an unknown injection: service:store

on this line:

  var session = container.lookup(Configuration.session);

in simple-auth.amd.js

@NullVoxPopuli do you use ember-cli? There is clean example if not - https://github.com/simplabs/ember-simple-auth/blob/master/examples/4-authenticated-account.html

I do use ember-cli.

here are my versions of things:

"ember": "1.13.10",
"ember-cli": "1.13.8",
"ember-simple-auth": "0.8.0",
"ember-data": "1.13",

if this is an ember 2 thing, I can finish up getting rid of my deprecation warnings and upgrade

Its not, it should work with 1.13.x.
I am wondering if problem is with store: service(), or with session itself.
If error persists when you comment out this then there must be wrong something like file name, or configuration. Also check that your session is in app/sessions/application.js

//config/environment.js
module.exports = function (environment) {
  var ENV = {
    'simple-auth': {
      session: 'session:application',
    }
  }
}