Add backend support for zone tooltips

backend/right_tree/api/migrations/0013_zone_tooltiptext.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.8 on 2021-12-12 22:51
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('api', '0012_alter_plant_maxheight'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='zone',
+            name='tooltipText',
+            field=models.CharField(blank=True, max_length=500, null=True),
+        ),
+    ]