PostgreSQL with the PGvector extension for RAG: Added Docker Compose configuration

[CodelineAtyab]

What's in this PR?

This PR adds a ready-to-use Docker Compose configuration that integrates PostgreSQL with the PGvector extension, enabling powerful Retrieval-Augmented Generation (RAG) capabilities in n8n workflows.

Technical Details

• Example RAG workflow visualization using PGVector

• Utilizes pgvector/pgvector:pg17 image with vector extension pre-installed
• Automatically creates the necessary database schema for vector embeddings
• Provides port mapping to avoid conflicts with existing PostgreSQL installations

[CodelineAtyab]

Tested two workflows on n8n as shown in the diagram