Improve documentation (usage/installation/example)

Author: vdjagilev

README.md

@@ -4,6 +4,10 @@ A tool that allows you to convert NMAP XML output to html/csv/json/markdown.
 
 ## Usage
 
+```
+nmap-formatter [path-to-nmap.xml] [html|csv|md|json] [flags]
+```
+
 Convert XML output to nicer HTML
 
 ```
@@ -16,4 +20,47 @@ or Markdown
 nmap-formatter [path-to-nmap.xml] md > some-markdown.md
 ```
 
+### Flags
+
+* `--down-hosts` includes hosts that are down in the template (html, md)
+* `-f, --file [filename]` outputs result to the file (by default output goes to STDOUT)
+* `--help` display help message
+
+## Installation
+
+### Using Go
+
+```
+go install github.com/vjdagilev/nmap-formatter@latest
+```
+
+### Download Binary
+
+Choose version from Release page and download it:
+
+```
+curl https://github.com/vdjagilev/nmap-formatter/releases/download/v0.0.2-alpha/nmap-formatter-linux-amd64.tar.gz --output nmap-formatter.tar.gz -L
+tar -xzvf nmap-formatter.tar.gz
+./nmap-formatter --help
+```
+
+### Compile
+
+```
+git clone [email protected]:vdjagilev/nmap-formatter.git
+cd nmap-formatter
+go mod tidy
+go build
+# or 
+go run . path/to/nmap.xml html
+```
+
+## Example
+
+Example of HTML generated output from (https://nmap.org/book/output-formats-xml-output.html)
+
+```
+nmap-formatter basic-example.xml html
+```
 
+![Basic HTML Example](docs/images/basic-example-html.png)