README update

Author: dhamith93

README.md

@@ -2,3 +2,25 @@
 Command-line tool to load csv files and run sql commands 
 
 [![Go](https://github.com/dhamith93/csv-sql/actions/workflows/go.yml/badge.svg)](https://github.com/dhamith93/csv-sql/actions/workflows/go.yml)
+
+## Usage
+
+csv-sql supports loading and saving results as CSV files with data processing with SQLite compatible sql commands
+
+### Loading a file
+```
+LOAD /path/to/file.csv table_name
+```
+
+### Creating a new table with a select query
+```sql
+CREATE TABLE emp_user AS SELECT emp.emp_id, emp.name, user.user_name, user.role FROM emp INNER JOIN user ON emp.user_id = user.id
+```
+
+### Saving a table as a csv
+```
+SAVE table_name /path/to/save.csv
+```
+## Screenshots
+
+![](screenshots/screenshot_01.png)