feat: add storage options comparison for grocery receipt tracking

Co-authored-by: aider (openai/unsloth/Qwen3-Coder-Next) <aider@aider.chat>

README.md

@@ -21,6 +21,54 @@ This project helps you:
 - Visualize price changes with charts and graphs
 - Generate reports on spending patterns and savings opportunities
 
+## Storage Options
+
+When storing your grocery receipt data, you have several options:
+
+### CSV Files
+**Advantages:**
+- Simple, human-readable format
+- Easy to share and import into other tools (Excel, Google Sheets)
+- No database software required
+- Good for small datasets
+
+**Disadvantages:**
+- No data validation or constraints
+- Difficult to query across multiple files
+- Performance degrades with large datasets
+- No built-in concurrency support
+- Not ideal for tracking relationships between data (e.g., items to receipts)
+
+### SQLite Database
+**Advantages:**
+- Lightweight, serverless database engine
+- Single file storage (easy to backup and transfer)
+- Supports SQL queries for complex analysis
+- ACID compliant for data integrity
+- No separate database server required
+- Excellent for desktop/local applications
+
+**Disadvantages:**
+- Limited concurrent write access
+- Not suitable for multi-user web applications
+- Database size can grow with large datasets
+
+### PostgreSQL/MySQL Database
+**Advantages:**
+- Robust, enterprise-grade database systems
+- Excellent for multi-user applications
+- Advanced querying capabilities
+- Strong concurrency support
+- Scalable for large datasets
+
+**Disadvantages:**
+- Requires separate database server setup
+- More complex configuration
+- Overkill for personal/local use cases
+
+### Recommendation for This Project
+For tracking personal grocery receipts with price comparison features, **SQLite** is the recommended option. It provides the benefits of a proper database (structured queries, data integrity, relationships) while remaining simple to set up and maintain as a single file. This aligns with the current implementation in the "Getting Started" section.
+
 ## Getting Started
 
 1. Clone this repository