diff --git a/database/migrations/2018_02_10_151150_remove_unique_index_on_external_id_column.php b/database/migrations/2018_02_10_151150_remove_unique_index_on_external_id_column.php
new file mode 100644
index 000000000..b587cdcb0
--- /dev/null
+++ b/database/migrations/2018_02_10_151150_remove_unique_index_on_external_id_column.php
@@ -0,0 +1,32 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class RemoveUniqueIndexOnExternalIdColumn extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->dropUnique(['external_id']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->unique(['external_id']);
+        });
+    }
+}