Update README.md

Author: ghost1face

README.md

@@ -2,6 +2,8 @@
 
 netstandard library for detecting file types by 'magic numbers', similar to the `file` command in Linux/Unix. Useful for validating file uploads instead of trusting file extensions.
 
+[![NuGet](https://img.shields.io/nuget/v/FileTypeInterrogator.svg?style=flat-square&label=nuget)](https://www.nuget.org/packages/FileTypeInterrogator/)
+
 # Usage
 
 ```
@@ -29,4 +31,4 @@ IFileTypeInterrogator interrogator = new CustomFileTypeInterrogator("path_to_cus
 FileTypeInfo fileTypeInfo = interrogator.DetectType(...);
 ```
 
-It is best to create a single instance and manage it's lifetime through an IOC/DI Container.
+It is best to create a single instance and manage it's lifetime through an IOC/DI Container.