Restructured project

- backend moved to backend directory
- added and initialized frontend with vue
- moved infrastructure files to infra directory

backend/migrations/000002_create_families.up.sql

@@ -0,0 +1,14 @@
+CREATE TABLE families
+(
+    id                 BIGSERIAL PRIMARY KEY,
+    name               TEXT      NOT NULL,
+    owner_id           BIGINT    NOT NULL REFERENCES users (id),
+    telegram_chat_id   BIGINT    NOT NULL,
+    telegram_chat_name TEXT,
+    created_at         TIMESTAMP NOT NULL DEFAULT NOW(),
+    updated_at         TIMESTAMP NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_families_owner_id ON families (owner_id);
+
+CREATE UNIQUE INDEX idx_families_chat_id ON families (telegram_chat_id);