Better description of filedrop

Author: zix99

README.md

@@ -2,6 +2,8 @@
 
 FileDrop is a simple NodeJS application to upload and share files on local networks.
 
+It is written to work completely offline.  That means you can host it on a private network or an internetless access point.
+
 ![Screenshot](screenshot.png)
 
 # Installing
@@ -21,6 +23,22 @@ filedrop --target /path/to/savedir
 docker run -d -p 8080:8080 zix99/filedrop:latest
 ```
 
+## From source
+
+First, clone the repo...
+
+Then:
+
+```bash
+npm install
+npm start
+```
+
+To develop:
+```bash
+npm run dev
+```
+
 # Configuration
 
 Filedrop uses the [rc](https://www.npmjs.com/package/rc) module for configuration.  To configure, simply use environment variables like `filedrop_`, use a `.filedroprc` file, or simply change `config.js`.