Rack reservations (#900)

* Initial work on rack reservations

* Added views for rack reservations

* Implemented ArrayFieldSelectMultiple form widget

* Implemented API endpoints for rack reservations

* Tweaked the database migration

netbox/dcim/migrations/0026_add_rack_reservations.py

@@ -0,0 +1,33 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.4 on 2017-02-16 18:43
+from __future__ import unicode_literals
+
+from django.conf import settings
+import django.contrib.postgres.fields
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('dcim', '0025_devicetype_add_interface_ordering'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='RackReservation',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('units', django.contrib.postgres.fields.ArrayField(base_field=models.PositiveSmallIntegerField(), size=None)),
+                ('created', models.DateTimeField(auto_now_add=True)),
+                ('description', models.CharField(max_length=100)),
+                ('rack', models.ForeignKey(editable=False, on_delete=django.db.models.deletion.CASCADE, related_name='reservations', to='dcim.Rack')),
+                ('user', models.ForeignKey(editable=False, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL)),
+            ],
+            options={
+                'ordering': ['created'],
+            },
+        ),
+    ]