Added new Office category.

Resolves: https://github.com/ziadoz/awesome-php/pull/183/files

README.md

 	- [Logging](#logging)
 	- [E-commerce](#e-commerce)
 	- [PDF](#pdf)
+	- [Office](#office)
 	- [Database](#database)
 	- [Migrations](#migrations)
 	- [NoSQL](#nosql)
 * [Snappy](https://github.com/KnpLabs/snappy) - A PDF and image generation library.
 * [WKHTMLToPDF](https://github.com/antialize/wkhtmltopdf) - A tool to convert HTML to PDF.
 
+## Office
+*Libraries for working with office suite documents.*
+
+https://github.com/PHPOffice
+[PHPWord](https://github.com/PHPOffice/PHPWord) - A library for working with Microsoft Word documents.
+[PHPExcel](https://github.com/PHPOffice/PHPExcel) - A library for working with Microsoft Excel documents.
+[PHPPowerPoint](https://github.com/PHPOffice/PHPPowerPoint) - A library for working with Microsoft Word documents.
+[ExcelAnt](https://github.com/Wisembly/ExcelAnt) - A library for manipulating Microsoft Excel documents.
+
 ## Database
 *Libraries for interacting with databases using object-relational mapping (ORM) or datamapping techniques.*