add index for Alias custom_domain_id and directory_id columns

app/models.py

@@ -1160,7 +1160,7 @@ class Alias(Base, ModelMixin):
     enabled = sa.Column(sa.Boolean(), default=True, nullable=False)
 
     custom_domain_id = sa.Column(
-        sa.ForeignKey("custom_domain.id", ondelete="cascade"), nullable=True
+        sa.ForeignKey("custom_domain.id", ondelete="cascade"), nullable=True, index=True
     )
 
     custom_domain = orm.relationship("CustomDomain", foreign_keys=[custom_domain_id])
@@ -1172,7 +1172,7 @@ class Alias(Base, ModelMixin):
 
     # to know whether an alias belongs to a directory
     directory_id = sa.Column(
-        sa.ForeignKey("directory.id", ondelete="cascade"), nullable=True
+        sa.ForeignKey("directory.id", ondelete="cascade"), nullable=True, index=True
     )
 
     note = sa.Column(sa.Text, default=None, nullable=True)

migrations/versions/2022_022617_5047fcbd57c7_.py

@@ -0,0 +1,31 @@
+"""empty message
+
+Revision ID: 5047fcbd57c7
+Revises: 9282e982bc05
+Create Date: 2022-02-26 17:51:03.379676
+
+"""
+import sqlalchemy_utils
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '5047fcbd57c7'
+down_revision = '9282e982bc05'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_index(op.f('ix_alias_custom_domain_id'), 'alias', ['custom_domain_id'], unique=False)
+    op.create_index(op.f('ix_alias_directory_id'), 'alias', ['directory_id'], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f('ix_alias_directory_id'), table_name='alias')
+    op.drop_index(op.f('ix_alias_custom_domain_id'), table_name='alias')
+    # ### end Alembic commands ###