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

.gitignore

@@ -1,7 +1,8 @@
-.direnv
 .env
 /coverage
 /target
+/.sqls
+/examples/target
 
 # Devenv
 .devenv*
@@ -17,6 +18,7 @@ devenv.local.nix
 *~
 \#*\#
 .\#*
+.dir-locals.el
 
 # Vim files
 *.swp