Fix broken users table in database causing validation errors.

database/migrations/2018_02_25_160152_remove_default_null_value_on_table.php

@@ -0,0 +1,38 @@
+<?php
+
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class RemoveDefaultNullValueOnTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @throws \Exception
+     * @throws \Throwable
+     */
+    public function up()
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->string('external_id')->default(null)->change();
+        });
+
+        DB::transaction(function () {
+            DB::table('users')->where('external_id', '=' , 'NULL')->update([
+                'external_id' => null,
+            ]);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        // This should not be rolled back.
+    }
+}

database/migrations/2018_02_25_160604_define_unique_index_on_users_external_id.php

@@ -0,0 +1,32 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class DefineUniqueIndexOnUsersExternalId extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->index(['external_id']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->dropIndex(['external_id']);
+        });
+    }
+}