docs: extended README

README.md

@@ -7,3 +7,33 @@ SPDX-License-Identifier: AGPL-3.0-or-later
 # paperless-client
 
 ![pre-commit enabled](https://img.shields.io/badge/pre--commit-enabled-brightgreen?logo=pre-commit&logoColor=white)
+
+This simple client is a wrapper around the paperless-ng API. It allows you to
+upload documents to your paperless-ng instance. By design it doesn't use
+anything besides curl, so that it can be used in a wide range of environments,
+like Alpine Linux or OpenWRT.
+
+## Installation
+
+```text
+curl -ROLf1 https://git.schmidl.dev/schtobia/paperless-client/raw/branch/master/paperless.sh
+chmod +x paperless.sh
+echo BASEURL=<your paperless-ng instance> > .env
+echo TOKEN=<your paperless-ng token> >> .env
+```
+
+## Usage
+
+```text
+paperless.sh get_tasks | put_document <file>
+
+commands:
+    get_tasks       Get the list of tasks. This is not formatted, i.e. you'll
+                    have to pipe it yourself through a formatter.
+    put_document    Uploads the document under <file> to your paperless
+                    instance.
+
+return values:
+    If everything went alright, paperless.sh returns 0. Every other return
+    value indicates an error.
+```