new: add reranker example to readme

README.md

@@ -137,6 +137,21 @@ embeddings = list(model.embed(images))
 # ]
 ```
 
+### 🔄 Rerankers
+```python
+from typing import List
+from fastembed.rerank.cross_encoder import TextCrossEncoder
+
+query = "Who is maintaining Qdrant?"
+documents: List[str] = [
+    "This is built to be faster and lighter than other embedding libraries e.g. Transformers, Sentence-Transformers, etc.",
+    "fastembed is supported by and maintained by Qdrant.",
+]
+encoder = TextCrossEncoder(model_name='Xenova/ms-marco-MiniLM-L-6-v2')
+scores = encoder.rerank(query, documents)
+
+# [-11.48061752319336, 5.472434997558594]
+```
 
 ## ⚡️ FastEmbed on a GPU