Add .gitignore and secure environment configuration

- Added comprehensive .gitignore to prevent sensitive data commits
- Removed .env from git tracking to protect API tokens
- Created .env.example template for users to copy and configure
- Updated README with secure setup instructions using .env.example
- Prevents accidental exposure of Discogs API tokens and other secrets

.env.example

@@ -0,0 +1,9 @@
+# Discogs API Configuration
+# Get your API key from: https://www.discogs.com/settings/developers
+# Copy this file to .env and add your actual tokens
+
+# Required: Your Discogs User Token
+DISCOGS_USER_TOKEN=your_discogs_user_token_here
+
+# Optional: Custom User Agent (recommended)
+DISCOGS_USER_AGENT=YourAppName/1.0 +http://yourwebsite.com