Fix revision in migration filename

This has no functional impact, flask-migrate aka alembic was and will
continue to work as expected. It is just a cosmetic change for
consistency.

migrations/versions/31a4ed468b18_remove_all_settings_in_the_db.py

@@ -0,0 +1,32 @@
+"""Remove all setting in the DB
+
+Revision ID: 31a4ed468b18
+Revises: 4a666113c7bb
+Create Date: 2018-08-21 17:12:30.058782
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '31a4ed468b18'
+down_revision = '4a666113c7bb'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # delete all settings from "setting" table.
+    # PDA should work without initial settings in the DB
+    # Once user change the settings from UI, they will be
+    # written to the DB.
+    op.execute("DELETE FROM setting")
+
+    with op.batch_alter_table('setting') as batch_op:
+        # drop view column since we don't need it
+        batch_op.drop_column('view')
+
+def downgrade():
+    with op.batch_alter_table('setting') as batch_op:
+        batch_op.add_column(sa.Column('view', sa.String(length=64), nullable=True))