Added doctrine migrations and remove platform specific code from entities

data/migrations/Version20160819142757.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace ShlinkMigrations;
+
+use Doctrine\DBAL\Migrations\AbstractMigration;
+use Doctrine\DBAL\Schema\Schema;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+class Version20160819142757 extends AbstractMigration
+{
+    const MYSQL = 'mysql';
+    const SQLITE = 'sqlite';
+
+    /**
+     * @param Schema $schema
+     */
+    public function up(Schema $schema)
+    {
+        $db = $this->connection->getDatabasePlatform()->getName();
+        $table = $schema->getTable('short_urls');
+        $column = $table->getColumn('short_code');
+
+        if ($db === self::MYSQL) {
+            $column->setPlatformOption('collation', 'utf8_bin');
+        } elseif ($db === self::SQLITE) {
+            $column->setPlatformOption('collation', 'BINARY');
+        }
+    }
+
+    /**
+     * @param Schema $schema
+     */
+    public function down(Schema $schema)
+    {
+        $db = $this->connection->getDatabasePlatform()->getName();
+    }
+}