Started work on making the public role/user configurable

Create a new 'public' guest user and made the public
role visible on role setting screens.

database/migrations/2016_09_29_101449_remove_hidden_roles.php

@@ -0,0 +1,66 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class RemoveHiddenRoles extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        // Remove the hidden property from roles
+        Schema::table('roles', function(Blueprint $table) {
+            $table->dropColumn('hidden');
+        });
+
+        // Add column to mark system users
+        Schema::table('users', function(Blueprint $table) {
+            $table->string('system_name')->nullable()->index();
+        });
+
+        // Insert our new public system user.
+        $publicUserId = DB::table('users')->insertGetId([
+            'email' => 'guest@example.com',
+            'name' => 'Guest',
+            'system_name' => 'public',
+            'email_confirmed' => true,
+            'created_at' => \Carbon\Carbon::now(),
+            'updated_at' => \Carbon\Carbon::now(),
+        ]);
+        
+        // Get the public role
+        $publicRole = DB::table('roles')->where('system_name', '=', 'public')->first();
+
+        // Connect the new public user to the public role
+        DB::table('role_user')->insert([
+            'user_id' => $publicUserId,
+            'role_id' => $publicRole->id
+        ]);
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::table('roles', function(Blueprint $table) {
+            $table->boolean('hidden')->default(false);
+            $table->index('hidden');
+        });
+
+        DB::table('users')->where('system_name', '=', 'public')->delete();
+
+        Schema::table('users', function(Blueprint $table) {
+            $table->dropColumn('system_name');
+        });
+
+        DB::table('roles')->where('system_name', '=', 'public')->update(['hidden' => true]);
+    }
+}