Change 'is_active' column names to 'archived'

Changed the name of the `is_active` columns to `archived` in these
tables:
* `service_email_reply_to`
* `service_sms_senders`
* `service_letter_contacts`

These columns were not being used yet, but because we describe Templates as
'archived', this keeps the names consistent.

The default value of these columns now needs to be False, not True.

migrations/versions/0186_rename_is_active_columns.py

@@ -0,0 +1,33 @@
+"""
+
+Revision ID: 0186_rename_is_active_columns
+Revises: 0185_add_is_active_to_reply_tos
+Create Date: 2018-04-27 16:35:41.824981
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = '0186_rename_is_active_columns'
+down_revision = '0185_add_is_active_to_reply_tos'
+
+
+def upgrade():
+    op.alter_column('service_email_reply_to', 'is_active', new_column_name='archived', server_default=sa.false())
+    op.alter_column('service_letter_contacts', 'is_active', new_column_name='archived', server_default=sa.false())
+    op.alter_column('service_sms_senders', 'is_active', new_column_name='archived', server_default=sa.false())
+
+    op.execute("Update service_email_reply_to set archived = False")
+    op.execute("Update service_letter_contacts set archived = False")
+    op.execute("Update service_sms_senders set archived = False")
+
+
+def downgrade():
+    op.alter_column('service_email_reply_to', 'archived', new_column_name='is_active', server_default=sa.true())
+    op.alter_column('service_letter_contacts', 'archived', new_column_name='is_active', server_default=sa.true())
+    op.alter_column('service_sms_senders', 'archived', new_column_name='is_active', server_default=sa.true())
+
+    op.execute("Update service_email_reply_to set is_active = True")
+    op.execute("Update service_letter_contacts set is_active = True")
+    op.execute("Update service_sms_senders set is_active = True")