feat(examples): add PostgreSQL example with user relationship

Adds an example demonstrating user, comment, and follower relationship
including:
- User management with profiles
- Comments (not really useful, just for showcasing)
- Follower/follozing relationships
- Ineractive CLI interface with CRUD operations
- Database migrations for the example schema

examples/postgres/users-comments-and-followers/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "georm-users-comments-and-followers"
+workspace = "../../../"
+publish = false
+version.workspace = true
+edition.workspace = true
+
+[dependencies]
+georm = { path = "../../.." }
+sqlx = { workspace = true }
+clap = { version = "4.4", features = ["derive"] }
+inquire = "0.7.5"
+thiserror = "2.0.11"
+tokio = { version = "1.43.0", features = ["full"] }