docs: add basic development instructions

README.md

 # Categories management plugin
 
-A __PeerTube__ plugin to add or delete video categories.
+A __PeerTube__ plugin to manage video categories.
+
+## Development
+
+1. Install and start a __PeerTube__ *dev* instance:
+> https://docs.joinpeertube.org/contribute-plugins?id=test-your-plugintheme
+
+2. Install the plugin from your __PeerTube__ directory: 
+```
+node ./dist/server/tools/peertube.js plugins install --path ~/workspace/peertube/peertube-plugin-categories
+```
+
+> You must re-install the extension to test each updates.
+
+## Resources
+
+- https://docs.joinpeertube.org/contribute-plugins
+- https://framagit.org/framasoft/peertube/official-plugins/-/blob/master/peertube-plugin-hello-world/main.js
 
 ## License
 

package.json

 {
   "name": "peertube-plugin-categories",
   "version": "1.0.0",
-  "description": "A PeerTube plugin to add or hide video categories.",
+  "description": "Manage video categories.",
   "license": "EUPL-1.2",
   "engine": {
     "peertube": ">=3.2.0"