Add listener to save commit on blob update

Update the usage of `$this->em->{persist,create}` to
`$this->{persist,create}` to ensure the action isn't dispatched when
saving relations, so we can hook into the blob save action to persist
the commit.

Fixes #866.

app/Database/Repository/AbstractRepository.php

@@ -5,6 +5,7 @@
 use Intraxia\Gistpen\Contract\Repository;
 use Intraxia\Gistpen\Model\Blob;
 use Intraxia\Gistpen\Model\Language;
+use Intraxia\Gistpen\Model\Commit;
 use Intraxia\Gistpen\Model\State;
 use Intraxia\Jaxion\Contract\Axolotl\EntityManager;
 use Intraxia\Jaxion\Axolotl\Collection;
@@ -100,6 +101,14 @@ protected function fill_relations( Model $model, array $params ) {
 						}
 					}
 					break;
+				case 'commits':
+					$value = $this->em->find_by( Commit::class, array_merge( $params, array(
+						'repo_id'     => $model->get_primary_id(),
+						'post_status' => 'any',
+						'order'       => 'ASC',
+						'orderby'     => 'date',
+					) ) );
+					break;
 			}
 
 			if ( null !== $value ) {

app/Database/Repository/WordPressPost.php

@@ -254,7 +254,7 @@ public function create( $class, array $data = array(), array $options = array()
 				$blob_data['repo_id'] = $model->get_primary_id();
 				$blob_data['status']  = $model->get_attribute( 'status' );
 
-				$blob = $this->em->create( Blob::class, $blob_data, array(
+				$blob = $this->create( Blob::class, $blob_data, array(
 					'unguarded' => true,
 				) );
 
@@ -338,7 +338,7 @@ public function persist( Model $model ) {
 				$blob->status  = $model->get_attribute( 'status' );
 				$blob->reguard();
 
-				$this->em->persist( $blob );
+				$this->persist( $blob );
 			}
 
 			foreach ( $deleted_blobs as $deleted_blob ) {
@@ -389,7 +389,7 @@ public function persist( Model $model ) {
 			$states = new Collection( State::class );
 
 			foreach ( $model->states as $state ) {
-				$state = $this->em->persist( $state );
+				$state = $this->persist( $state );
 
 				if ( ! is_wp_error( $state ) ) {
 					$states = $states->add( $state );

test/Integration/Http/Blob/CreateTest.php

@@ -83,11 +83,16 @@ public function test_saves_blob_with_filename_to_repo() {
 		$repo = $this->app->make( 'database' )
 			->find( Repo::class, $this->repo->ID, [
 				'with' => [
-					'blobs' => [
+					'blobs'   => [
 						'with' => [
 							'language' => [],
 						],
 					],
+					'commits' => [
+						'with' => [
+							'states' => [],
+						],
+					],
 				],
 			] );
 
@@ -108,6 +113,7 @@ public function test_saves_blob_with_filename_to_repo() {
 			],
 		] );
 		$this->assertSame( $blob->filename, $this->blob->filename );
+		$this->assertCount( 2, $repo->commits );
 	}
 
 	public function test_saves_blob_with_filename_code_and_language() {