set indexes on gene columns

backend/metagenedb/apps/catalog/migrations/0028_index_source_and_functions.py

+# Generated by Django 3.1.7 on 2021-03-26 13:48
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('catalog', '0027_fix_deprecated_jsonfield'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='gene',
+            name='functions',
+            field=models.ManyToManyField(db_index=True, through='catalog.GeneFunction', to='catalog.Function'),
+        ),
+        migrations.AlterField(
+            model_name='gene',
+            name='source',
+            field=models.CharField(choices=[('undef', 'Undefined'), ('igc', 'IGC'), ('virgo', 'Virgo')], db_index=True, default='undef', max_length=10),
+        ),
+    ]

backend/metagenedb/apps/catalog/models/gene.py

@@ -24,13 +24,13 @@ class Gene(models.Model):
     name = models.CharField(max_length=100, unique=True)
     sequence = models.TextField(blank=True)
     length = models.PositiveIntegerField(db_index=True)
-    functions = models.ManyToManyField(Function, through='GeneFunction')
+    functions = models.ManyToManyField(Function, db_index=True, through='GeneFunction')
     taxonomy = models.ForeignKey(
         'Taxonomy', related_name='genes',
         on_delete=models.SET_NULL,
         null=True, blank=True
     )
-    source = models.CharField(max_length=10, choices=SOURCE_CHOICES, default=UNDEFINED)
+    source = models.CharField(max_length=10, db_index=True, choices=SOURCE_CHOICES, default=UNDEFINED)
 
     def __str__(self) -> str:
         return self.gene_id