add expenses management

internal/db/migrations/00007_create_expenses_tables.sql

@@ -0,0 +1,42 @@
+-- +goose Up
+-- +goose StatementBegin
+CREATE TABLE IF NOT EXISTS expenses (
+    id TEXT PRIMARY KEY NOT NULL,
+    space_id TEXT NOT NULL,
+    created_by TEXT NOT NULL,
+    description TEXT NOT NULL,
+    amount_cents INTEGER NOT NULL,
+    type TEXT NOT NULL CHECK (type IN ('expense', 'topup')),
+    date TIMESTAMP NOT NULL,
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (space_id) REFERENCES spaces(id) ON DELETE CASCADE,
+    FOREIGN KEY (created_by) REFERENCES users(id) ON DELETE CASCADE
+);
+
+CREATE TABLE IF NOT EXISTS expense_tags (
+    expense_id TEXT NOT NULL,
+    tag_id TEXT NOT NULL,
+    PRIMARY KEY (expense_id, tag_id),
+    FOREIGN KEY (expense_id) REFERENCES expenses(id) ON DELETE CASCADE,
+    FOREIGN KEY (tag_id) REFERENCES tags(id) ON DELETE CASCADE
+);
+
+CREATE TABLE IF NOT EXISTS expense_items (
+    expense_id TEXT NOT NULL,
+    item_id TEXT NOT NULL,
+    PRIMARY KEY (expense_id, item_id),
+    FOREIGN KEY (expense_id) REFERENCES expenses(id) ON DELETE CASCADE,
+    FOREIGN KEY (item_id) REFERENCES list_items(id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS idx_expenses_space_id ON expenses(space_id);
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+DROP INDEX IF EXISTS idx_expenses_space_id;
+DROP TABLE IF EXISTS expense_items;
+DROP TABLE IF EXISTS expense_tags;
+DROP TABLE IF EXISTS expenses;
+-- +goose StatementEnd