indexing the not after field in the cert table

lemur/migrations/versions/b33c838cb669_.py

@@ -0,0 +1,26 @@
+"""adding index on the not_after field
+
+Revision ID: b33c838cb669
+Revises: 318b66568358
+Create Date: 2019-05-30 08:42:05.294109
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'b33c838cb669'
+down_revision = '318b66568358'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_index('ix_certificates_not_after', 'certificates', [sa.text('not_after DESC')], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index('ix_certificates_not_after', table_name='certificates')
+    # ### end Alembic commands ###