FEATURE: add functionality for creating new widget.

This commit adds functionality for creating widget of whatever type. Controller calls widget admin handler, which renders and handles input form.

database/migrations/2016_02_14_142507_AddIdToWidgetTypes.php

@@ -0,0 +1,78 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class AddIdToWidgetTypes extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        // drop foreign key from widgets table
+        try {
+            Schema::table('widgets', function (Blueprint $table) {
+                $table->dropForeign('fk_widget_widget_type1');
+            });
+        } catch (Exception $e) {
+            Schema::table('widgets', function (Blueprint $table) {
+                $table->dropForeign('widgets_widget_type_handler_foreign');
+            });
+        }
+
+        // try to drop primary key (should be on handler column)
+        Schema::table('widget_types', function (Blueprint $table) {
+            $table->dropIndex('PRIMARY');
+        });
+
+        // add new column "id" with autoincrement and make handler unique, not primary
+        Schema::table('widget_types', function (Blueprint $table) {
+            $table->integer('id', true)
+                  ->first();
+
+            $table->string('handler')
+                  ->unique()
+                  ->change();
+        });
+
+        // create foreign constraint active again
+        Schema::table('widgets', function (Blueprint $table) {
+            $table->foreign('widget_type_handler')
+                  ->references('handler')
+                  ->on('widget_types')
+                  ->onDelete('cascade');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::table('widgets', function (Blueprint $table) {
+            $table->dropForeign('widgets_widget_type_handler_foreign');
+        });
+
+        Schema::table('widget_types', function (Blueprint $table) {
+            $table->dropColumn('id');
+            $table->dropIndex('widget_types_handler_unique');
+            $table->string('handler')
+                  ->primary()
+                  ->change();
+        });
+        // create foreign constraint active again
+        Schema::table('widgets', function (Blueprint $table) {
+            $table->foreign('widget_type_handler')
+                  ->references('handler')
+                  ->on('widget_types')
+                  ->onDelete('cascade');
+        });
+
+    }
+}