put some good stuff in the readme

README.md

@@ -1,5 +1,89 @@
-this is a work in progress
+Sup is a small and simple process supervisor. Configuration file is sup.toml in
+the current directory.
 
-the idea is to be a sort of process/session manager sorta .xinitrc replacement
-thing for x. configure the stuff you want to run in sup.toml then run sup. there
-is no documentation at this time, so probably don't use this.
+## Installing
+
+```
+cargo install https://gitlab.com/rascul/sup
+```
+
+## Running
+
+Sup must find the config file sup.toml in the current directory.
+
+## Features
+
+### Restart
+
+Sup can be configured to restart an application when it stops. There are three
+conditions sup can watch for:
+
+* Success: In this case, the application has done a normal shutdown and the
+exit status is 0.
+* Failure: If the application exits with a non zero exit status it is
+considered to have failed.
+* Terminated: The application was killed by some other mechanism.
+
+### Holds
+
+A hold may be placed on any number of application. If there are any holds, sup
+will keep track and while any held applications are running, sup will not exit.
+When all held applications are no longer running, and are not configured to
+restart anymore, sup will close the other applications and shutdown. If no holds
+are specified, sup will just keep running until it's killed.
+
+## Configuration File
+
+The configuration file is sup.toml and will be found in the current directory
+when starting sup. This will change in the future. Sup uses the
+[toml](https://github.com/toml-lang/toml) format to describe each application
+to supervise.
+
+### `[[App]]`
+
+Each application instance to monitor will have an `[[App]]` section. The apps
+will be started in the order as read from the file.
+
+#### Required Entries
+
+* name: The name of the application.
+* command: The command to run, including path if necessary.
+* args: An array of arguments to pass with the command. May be an empty array.
+
+#### Optional Entries
+
+* restart_on_success: Restart the app if it exits successfully. (Default: false)
+* restart_on_failure: Restart the app if it fails. (Default: false)
+* restart_on_terminate: Restart the app if it is terminated. (Default: false)
+* wait: Don't run the next app until this one is finished. (Default: false)
+* hold: Don't exit sup until this app has finished. (Default: false)
+
+### Example
+
+```
+[[app]]
+name = "x resource"
+command = "xrdb"
+args = ["~/.Xresources"]
+wait = true
+
+[[app]]
+name = "terminal"
+command = "alacritty"
+args = []
+restart_on_success = false
+restart_on_failure = true
+restart_on_terminate = true
+hold = true
+
+[[app]]
+name = "environment"
+command = "alacritty"
+args = ["-e", "env"]
+
+[[app]]
+name = "window manager"
+command = "twm"
+args = []
+hold = true
+```