add documentation

README.md

@@ -1,2 +1,26 @@
 # sadExtractor
 sadExtractor is a simple recon tool that extract all links from a web page. 
+
+
+## Install
+
+If you have Go installed and configured (i.e. with `$GOPATH/bin` in your `$PATH`):
+
+```
+go install -v github.com/SaDs3c/sadExtractor@latest
+```
+
+Otherwise [download a release for your platform](https://github.com/SaDs3c/sadExtractor/releases).
+To make it easier to execute you can put the binary in your `$PATH`.
+
+## Usage
+
+Single URL: 
+```
+sadExtractor -d <domain> -o output.txt
+```
+
+Multiple URL in File:
+```
+sadExtractor -l urls.txt -o output.txt
+```