Update README

README.md

@@ -1,6 +1,6 @@
 # STRINGX
 
-STRINGX is a [STRING](string-db.org) API client using [HTTPX](https://www.python-httpx.org)
+STRINGX is a [STRING](https://string-db.org) API client using [HTTPX](https://www.python-httpx.org).
 
 ## Install
 
@@ -12,8 +12,28 @@ pip install stringx
 
 ```python
 import stringx
+```
+
+You can call API endpoints directly
+
+```python
+identifiers = stringx.map_identifiers(["edin", "atta"], species=7227)
+```
+
+or instantiate a customized client where you can specify the API version or your *caller identity*.
 
-with stringx.Client() as client:
+
+```python
+import stringx
+
+with stringx.Client(base_url="https://version-11-0.string-db.org") as client:
     identifiers = client.map_identifiers(["edin", "atta"], species=7227)
 
 ```
+
+### API Endpoints
+
+| Method                           | API URL                         | **stringx**              |
+| -------------------------------- | ------------------------------- | ------------------------ |
+| Mapping identifiers              | /api/json/get_string_ids?       | `map_identifiers()`      |
+| Getting the interaction partners | /api/json/interaction_partners? | `interaction_partners()` |