message: rename variable to match the already-updated implementation
diff: @@ -7,7 +7,7 @@ const { Registry, Container } = require('@cardstack/di');
  describe('schema/validation', function() {
  - let schema, gitDataSource;
  + let schema, ephemeralDataSource;
  before(async function() {
  let factory = new JSONAPIFactory();
  @@ -15,7 +15,7 @@ describe('schema/validation', function() {
  factory.addResource('plugin-configs').withAttributes({ module: '@cardstack/ephemeral' });
  - gitDataSource = factory.addResource('data-sources')
  + ephemeralDataSource = factory.addResource('data-sources')
  .withAttributes({
  sourceType: '@cardstack/ephemeral',
  params: {
  @@ -27,10 +27,10 @@ describe('schema/validation', function() {
  factory.addResource('plugin-configs').withAttributes({
  module: '@cardstack/hub'
  - }).withRelated('defaultDataSource', gitDataSource);
  + }).withRelated('defaultDataSource', ephemeralDataSource);
  let articleType = factory.addResource('content-types', 'articles')
  - .withRelated('data-source', gitDataSource);
  + .withRelated('data-source', ephemeralDataSource);
  articleType.withRelated('fields', [
  factory.addResource('fields', 'title')
  @@ -256,7 +256,7 @@ describe('schema/validation', function() {
  expect(schema.types.get('articles').dataSource).is.ok;
  expect(schema.types.get('articles').dataSource.writer).is.ok;
  - expect(schema.types.get('articles').dataSource).has.property('id', gitDataSource.id);
  + expect(schema.types.get('articles').dataSource).has.property('id', ephemeralDataSource.id);
  // this relies on knowing a tiny bit of writer's internals. When
  // we have a more complete plugin system we should just inject a
  // fake writer plugin for this test to avoid the coupling.
  @@ -265,14 +265,14 @@ describe('schema/validation', function() {
  });
  it("can lookup up an indexer on a data source", async function() {
  - let source = schema.dataSources.get(gitDataSource.id);
  + let source = schema.dataSources.get(ephemeralDataSource.id);
  expect(source).ok;
  expect(source.indexer).ok;
  });
  it("uses default data source", async function() {
  expect(schema.types.get('things-with-defaults').dataSource).is.ok;
  - expect(schema.types.get('things-with-defaults').dataSource).has.property('id', gitDataSource.id);
  + expect(schema.types.get('things-with-defaults').dataSource).has.property('id', ephemeralDataSource.id);
  });
  it("applies creation default", async function() {
  