feat: Update project structure and configuration files

backend/database/migrations/20250322103119_create_users.sql

@@ -0,0 +1,19 @@
+-- +goose Up
+-- +goose StatementBegin
+CREATE TABLE users(
+    id SERIAL8 PRIMARY KEY,
+    created_at timestamp NOT NULL DEFAULT now(),
+    updated_at timestamp NOT NULL DEFAULT now(),
+    deleted_at timestamp,
+    status int2 NOT NULL DEFAULT 0,
+    open_id varchar(128) NOT NULL UNIQUE,
+    username varchar(128) NOT NULL,
+    avatar varchar(128)
+);
+
+-- +goose StatementEnd
+-- +goose Down
+-- +goose StatementBegin
+DROP TABLE users;
+
+-- +goose StatementEnd