rename book_id in po table to booking_id to perform ORM relantionship

added relationship between booking and po
updated settings shows for different role
added function to display po for admin

database/migrations/2018_06_28_011717_rename_booking_foreignkey_in_po_table.php

@@ -0,0 +1,33 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class RenameBookingForeignkeyInPoTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::table('purchase_orders', function($table)
+        {
+            $table->dropForeign('book_id');
+            $table->integer('booking_id')->unsigned();
+            $table->foreign('booking_id')->references('id')->on('bookings');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        //
+    }
+}