[Cursor] Add detailed step-by-step tutorial with screenshots (#67)

This commit adds a comprehensive step-by-step tutorial that makes the setup process clearer and easier to follow. Changes include:

- Added detailed installation and configuration instructions
- Added screenshots for each major step
- Added a basic example (stock price visualization) to demonstrate Cursor's capabilities
- Updated README.md to reference the new tutorial

The tutorial addresses the confusion reported in #58 by providing clear visual guidance and detailed explanations for each step of the setup process.

Fixes #58

Author: grapeot

README.md

@@ -50,6 +50,8 @@ Devin impressed many by acting like an intern who writes its own plan, updates t
 
 ## Usage
 
+For a detailed walkthrough of setting up and using devin.cursorrules with Cursor, check out our [step-by-step tutorial](step_by_step_tutorial.md). This guide covers everything from initial Cursor setup to configuring devin.cursorrules and using the enhanced capabilities.
+
 1. Choose your setup method:
    - **Cookiecutter (Recommended)**: Follow the prompts after running the cookiecutter command
    - **Manual**: Copy the files you need from this repository