Add user invitation facilities RSM-5

Adds user invitation to teams, and framework for assigning taems
Also adds user acc. deletion.

database/migrations/2020_10_04_163715_team_has_vacancy.php

@@ -0,0 +1,43 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class TeamHasVacancy extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('team_has_vacancy', function(Blueprint $table){
+
+            $table->id();
+            $table->integer('team_id')->unsigned();
+            $table->bigInteger('vacancy_id')->unsigned();
+            $table->timestamps();
+
+            $table->foreign('team_id')
+                  ->references('id')
+                    ->on(config('teamwork.teams_table'));
+
+            $table->foreign('vacancy_id')
+                  ->references('id')
+                    ->on('vacancies');
+
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        //
+    }
+}