adding support for model aliases in archgw (#566)

* adding support for model aliases in archgw

* fixed PR based on feedback

* removing README. Not relevant for PR

---------

Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-136.local>

demos/use_cases/model_alias_routing/run_demo.sh

@@ -0,0 +1,60 @@
+#!/bin/bash
+set -e
+
+# Function to start the demo
+start_demo() {
+  # Step 1: Check if .env file exists
+  if [ -f ".env" ]; then
+    echo ".env file already exists. Skipping creation."
+  else
+    # Step 2: Create `.env` file and set API keys
+    if [ -z "$OPENAI_API_KEY" ]; then
+      echo "Error: OPENAI_API_KEY environment variable is not set for the demo."
+      exit 1
+    fi
+    if [ -z "$ANTHROPIC_API_KEY" ]; then
+      echo "Warning: ANTHROPIC_API_KEY environment variable is not set. Anthropic features may not work."
+    fi
+
+    echo "Creating .env file..."
+    echo "OPENAI_API_KEY=$OPENAI_API_KEY" > .env
+    if [ -n "$ANTHROPIC_API_KEY" ]; then
+      echo "ANTHROPIC_API_KEY=$ANTHROPIC_API_KEY" >> .env
+    fi
+    echo ".env file created with API keys."
+  fi
+
+  # Step 3: Start Arch
+  echo "Starting Arch with arch_config_with_aliases.yaml..."
+  archgw up arch_config_with_aliases.yaml
+
+  echo "\n\nArch started successfully."
+  echo "Please run the following CURL command to test model alias routing. Additional instructions are in the README.md file. \n"
+  echo "curl -sS -X POST \"http://localhost:12000/v1/chat/completions\" \
+    -H \"Authorization: Bearer test-key\" \
+    -H \"Content-Type: application/json\" \
+    -d '{
+      \"model\": \"arch.summarize.v1\",
+      \"max_tokens\": 50,
+      \"messages\": [
+        { \"role\": \"user\",
+          \"content\": \"Hello, please respond with exactly: Hello from alias arch.summarize.v1!\"
+        }
+      ]
+    }' | jq ."
+}
+
+# Function to stop the demo
+stop_demo() {
+  # Step 2: Stop Arch
+  echo "Stopping Arch..."
+  archgw down
+}
+
+# Main script logic
+if [ "$1" == "down" ]; then
+  stop_demo
+else
+  # Default action is to bring the demo up
+  start_demo
+fi