[docs] Root README links to DOCKER_SETUP.md which does not exist

[Emeka000]

Broken Documentation Link

File: README.md (line 67)

Problem

The root README directs contributors to a DOCKER_SETUP.md file for detailed local setup instructions, but that file does not exist in the repository:

See [DOCKER_SETUP.md](./DOCKER_SETUP.md) for detailed instructions and optional development tools.

A contributor following the getting-started steps will click this link and reach a 404. The docker-compose.yml exists at the root but is never explained.

Impact

• First-time contributors cannot follow the local setup guide
• There is no documentation of what services the Docker Compose stack provides (Postgres, Redis, ports, credentials)
• No documentation of optional dev tools mentioned in the broken link
• This is the primary entry point for open-source contributors — a broken link immediately blocks onboarding

Fix

Either:

1. Create DOCKER_SETUP.md covering:
   • Prerequisites (Docker, Node.js, Rust/Stellar CLI for contracts)
   • What docker-compose up -d starts (Postgres on port 5432, Redis on port 6379)
   • Default credentials and how to override them via .env
   • How to verify the stack is healthy
   • Common troubleshooting steps
2. Or inline the setup instructions directly in the root README and remove the broken link

The root README also has no links to the backend, frontend, or contracts READMEs — those should be added regardless.

[Spagero763]

@Spagero763 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

i can work on the readme file

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Spagero763 to this issue.