Celery refactoring, celery beat job in configuration

lemur/migrations/versions/9392b9f9a805_.py

@@ -0,0 +1,24 @@
+"""Add last_updated field to Pending Certs
+Revision ID: 9392b9f9a805
+Revises: 5ae0ecefb01f
+Create Date: 2018-09-17 08:33:37.087488
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '9392b9f9a805'
+down_revision = '5ae0ecefb01f'
+
+from alembic import op
+from sqlalchemy_utils import ArrowType
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.add_column('pending_certs', sa.Column('last_updated', ArrowType, server_default=sa.text('now()'), onupdate=sa.text('now()'),
+                                             nullable=False))
+
+
+def downgrade():
+    op.drop_column('pending_certs', 'last_updated')
+