Move to Symfony Flex

The structure changed completely.
Bundles are gone. Everything is flatten in the folder `src`.
I separated import & api controllers to avoid _pollution_ in the main controller folder.

migrations/Version20161104073720.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace DoctrineMigrations;
+
+use App\Doctrine\WallabagMigration;
+use Doctrine\DBAL\Schema\Schema;
+
+/**
+ * Added created_at index on entry table.
+ */
+class Version20161104073720 extends WallabagMigration
+{
+    private $indexName = 'IDX_entry_created_at';
+
+    public function up(Schema $schema): void
+    {
+        $entryTable = $schema->getTable($this->getTable('entry'));
+        $this->skipIf($entryTable->hasIndex($this->indexName), 'It seems that you already played this migration.');
+
+        $entryTable->addIndex(['created_at'], $this->indexName);
+    }
+
+    public function down(Schema $schema): void
+    {
+        $entryTable = $schema->getTable($this->getTable('entry'));
+        $this->skipIf(false === $entryTable->hasIndex($this->indexName), 'It seems that you already played this migration.');
+
+        $entryTable->dropIndex($this->indexName);
+    }
+}