feat: ✨ contact rethinked and user_contact created

src/feature/user_contact.rs

@@ -0,0 +1,7 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct UserContact {
+    pub user_id: i64,
+    pub contact_id: i64,
+}