short readme for flex flash (#2231)

Author: v0i0

flash_attn/cute/README.md

@@ -0,0 +1,26 @@
+# Flash Attention CUTE
+
+## Development Installation
+
+1. Clone the repository (if you haven't already):
+   ```bash
+   git clone https://github.com/Dao-AILab/flash-attention.git
+   cd flash-attention/cute
+   ```
+
+2. Install in editable mode with dev dependencies:
+   ```bash
+   pip install -e "./cute[dev]"
+   ```
+
+## Running Tests
+
+```bash
+pytest tests/cute/
+```
+
+## Linting
+
+```bash
+ruff check flash_attn/cute/
+```