Cli support (#50)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

README.md

@@ -3,18 +3,32 @@
 ### Install
 
 ```bash
+pip install ultralytics
+```
+Development
+```
 git clone https://github.com/ultralytics/ultralytics
 cd ultralytics
-python -m pip install --upgrade pip wheel
-pip install .  # (dev)
-# pip install ultralytics (production)
+pip install -e .
 ```
 
-### Usage
-
+## Usage
+### 1. CLI
+To simply use the latest Ultralytics YOLO models
+```bash
+yolo task=detect    mode=train  model=s.yaml ...
+          classify       infer        s-cls.yaml
+          segment        val          s-seg.yaml
+```
+### 2. Python SDK
+To use pythonic interface of Ultralytics YOLO model
 ```python
 import ultralytics
-from ultralytics import HUB, YOLO
+from ultralytics import YOLO
 
-ultralytics.checks()
+model = YOLO()
+model.new("s-seg.yaml") # automatically detects task type
+model.load("s-seg.pt") # load checkpoint
+model.train(data="coco128-segments", epochs=1, lr0=0.01, ...)
 ```
+If you're looking to modify YOLO for R&D or to build on top of it, refer to [Using Trainer]() Guide on our docs.