Added a new backend settings system

This can be used for saving runtime-configurable settings in the database.

migrations/versions/2024_01_03_1346-ccbb17aeda7c_added_settings_table.py

@@ -0,0 +1,32 @@
+"""Added Settings table.
+
+Revision ID: ccbb17aeda7c
+Revises: 92793c8a937c
+Create Date: 2024-01-03 13:46:41.362341
+"""
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "ccbb17aeda7c"
+down_revision = "92793c8a937c"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    """Perform the upgrade."""
+    op.create_table(
+        "setting",
+        sa.Column("key", sa.String(length=64), nullable=False),
+        sa.Column("value", sa.Text(), nullable=False),
+        sa.Column("last_updated", sa.DateTime(), nullable=False),
+        sa.PrimaryKeyConstraint("key"),
+    )
+    op.create_index(op.f("ix_setting_key"), "setting", ["key"], unique=False)
+
+
+def downgrade() -> None:
+    """Perform the downgrade."""
+    op.drop_index(op.f("ix_setting_key"), table_name="setting")
+    op.drop_table("setting")