Added alembic script to set low_emails from group name in reporting settings (if empty).

(Redmine issue: #7556)

lib/hawat/migrations/versions/87a0d55f56d5_set_email_in_reporting_settings_for_.py

+"""set email in reporting settings for group name
+
+Revision ID: 87a0d55f56d5
+Revises: d76d19d30c2c
+Create Date: 2023-02-21 11:00:12.434598
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '87a0d55f56d5'
+down_revision = 'd76d19d30c2c'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.execute("""
+UPDATE settings_reporting
+SET emails_low = ARRAY[groups.name]
+FROM groups
+WHERE
+  settings_reporting.emails_low = '{}' AND
+  groups.id = settings_reporting.group_id""")
+
+
+def downgrade():
+    # Downgrade is not possible, but also is not necessary,
+    # because it doesn't break anything in the old code.
+    pass