Install requirements via install script

Closes coop-cloud/abra#196.

README.md

@@ -39,13 +39,18 @@ Install the latest stable release:
 curl https://install.abra.coopcloud.tech | bash
 ```
 
-or the bleeding-edge development version:
+The source for this script is [here](./deploy/install.abra.coopcloud.tech/installer).
+
+You can pass options to the script like so (e.g. install the bleeding edge development version):
 
 ```sh
 curl https://install.abra.coopcloud.tech | bash -s -- --dev
 ```
 
-The source for this script is [here](./deploy/install.abra.coopcloud.tech/installer).
+Other options available are as follows:
+
+- **--no-prompt**: non-interactive installation
+- **--no-deps**: do not attempt to install [requirements](#requirements)
 
 ## Container