Merge pull request #200 from quetzyg/master

feat(*): change the user_id column type to unsignedInteger

src/Console/stubs/audits.stub

@@ -27,7 +27,7 @@ class CreateAuditsTable extends Migration
     {
         Schema::create('audits', function (Blueprint $table) {
             $table->increments('id');
-            $table->string('user_id')->nullable();
+            $table->unsignedInteger('user_id')->nullable();
             $table->string('event');
             $table->morphs('auditable');
             $table->text('old_values')->nullable();