However, we had that feedback a few time so there is a trick. If you write your result in ./result.json, we will process it as the result of your powershell script.
Am I able to install it on Windows? I need windows specific things, such as powershell remoting. One of the good things about Rundeck is that server acts as worker, and it runs on Windows without problems (Installing it is as simple as choco install rundeck). I can then use all windows tools, run applications (including GUI ones) etc. just the same as if I run them outside rundeck, using OTB powershell.
Regarding "Connection to the main database" as far as my use case is, all the settings could live in the file system json files or sqlite if that makes installation trivial for the use case of being very good job scheduler with options to create great jobs UI, logs and management of small number of users (which is a fairly common scenario).