docs(anthropic.md): add proxy usage tutorial to anthropic docs

docs/my-website/docs/providers/anthropic.md

@@ -1,3 +1,6 @@
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
 # Anthropic
 LiteLLM supports
 
@@ -45,7 +48,97 @@ for chunk in response:
     print(chunk["choices"][0]["delta"]["content"])  # same as openai format
 ```
 
+## OpenAI Proxy Usage 
 
+Here's how to call Anthropic with the LiteLLM Proxy Server
+
+### 1. Save key in your environment
+
+```bash
+export ANTHROPIC_API_KEY="your-api-key"
+```
+
+### 2. Start the proxy 
+
+```bash
+$ litellm --model claude-3-opus-20240229
+
+# Server running on http://0.0.0.0:8000
+```
+
+### 3. Test it
+
+
+<Tabs>
+<TabItem value="Curl" label="Curl Request">
+
+```shell
+curl --location 'http://0.0.0.0:8000/chat/completions' \
+--header 'Content-Type: application/json' \
+--data ' {
+      "model": "gpt-3.5-turbo",
+      "messages": [
+        {
+          "role": "user",
+          "content": "what llm are you"
+        }
+      ]
+    }
+'
+```
+</TabItem>
+<TabItem value="openai" label="OpenAI v1.0.0+">
+
+```python
+import openai
+client = openai.OpenAI(
+    api_key="anything",
+    base_url="http://0.0.0.0:8000"
+)
+
+# request sent to model set on litellm proxy, `litellm --model`
+response = client.chat.completions.create(model="gpt-3.5-turbo", messages = [
+    {
+        "role": "user",
+        "content": "this is a test request, write a short poem"
+    }
+])
+
+print(response)
+
+```
+</TabItem>
+<TabItem value="langchain" label="Langchain">
+
+```python
+from langchain.chat_models import ChatOpenAI
+from langchain.prompts.chat import (
+    ChatPromptTemplate,
+    HumanMessagePromptTemplate,
+    SystemMessagePromptTemplate,
+)
+from langchain.schema import HumanMessage, SystemMessage
+
+chat = ChatOpenAI(
+    openai_api_base="http://0.0.0.0:8000", # set openai_api_base to the LiteLLM Proxy
+    model = "gpt-3.5-turbo",
+    temperature=0.1
+)
+
+messages = [
+    SystemMessage(
+        content="You are a helpful assistant that im using to make a test request to."
+    ),
+    HumanMessage(
+        content="test from litellm. tell me why it's amazing in 1 sentence"
+    ),
+]
+response = chat(messages)
+
+print(response)
+```
+</TabItem>
+</Tabs>
 
 ## Supported Models