Add usage example

README.md

@@ -1,6 +1,33 @@
 # Harvester
 Python package for harvesting commonly available data, such as free proxy servers.
 
+## Modules
+### Proxy
+The `proxy` module will harvest proxies from URLs with the `fetch_list` function.
+
+It functions by running a regular expression against the HTTP response, looking for
+strings that match a `username:password@ip:port` pattern where username and password
+are optional.
+
+```python
+from harvester.proxy import fetch_list
+
+
+URLS = [
+    'https://api.openproxylist.xyz/socks4.txt',
+    'https://api.openproxylist.xyz/socks5.txt',
+    'https://api.proxyscrape.com/?request=displayproxies&proxytype=socks4',
+]
+
+
+def main():
+    """Main entry point."""
+    for url in URLS:
+        proxies = fetch_list(url)
+        print(proxies)
+
+```
+
 ## Testing
 ```
 pip install -r requirements.txt