fix(ember): provide default config path

When including this addon inside an Ember “app”, `app.options.configPath` is not defined.

This file is, under almost all but the most unusual circumstances, this file will be located at `config/environment` relative to the project root. By providing that as a default to fall back on in the case that the configuration option is not provided, including this addon inside an Ember app works again!

Author: alexlafroscia

packages/ember/index.js

@@ -2,6 +2,8 @@
 const fs = require('fs');
 const { resolve } = require('path');
 
+const DEFAULT_CONFIG_PATH = 'config/environment';
+
 function readSnippet(fileName) {
   return `<script>${fs.readFileSync(`${__dirname}/vendor/${fileName}`, 'utf8')}</script>`;
 }
@@ -20,7 +22,8 @@ module.exports = {
   getAddonConfig(app) {
     let config = {};
     try {
-      const fullConfigPath = resolve(app.project.root, app.options.configPath);
+      const configPath = app.options.configPath || DEFAULT_CONFIG_PATH;
+      const fullConfigPath = resolve(app.project.root, configPath);
       config = require(fullConfigPath)(app.env);
     } catch(_) {
       // Config not found