A WIP README

Need a good project and app name

README.md

@@ -2,6 +2,42 @@
 
 WIP for a docker batch scheduler
 
-Uses https://godoc.org/github.com/robfig/cron for cron expressions.
+## Usage
 
-Sets schedules based on label `cron.schedule="* * * * *"`
+$APPNAME requires access to the Docker, so it may need to be run as root, or, if in a Docker container, need the socket mapped as a volume.
+
+### Running $APPNAME
+
+As simple as:
+
+    ./$APPNAME
+
+It will then run in the foreground, periodically checking Docker for containers with labels containing a cron schedule.
+
+$APPNAME will periodically poll Docker for new containers or schedule changes.
+
+### Scheduling a container
+
+First, be sure your container is something that is not long running and will actually exit when complete. This is for batch runs and not keeping a service running. Docker should be able to do that on it's own with a restart policy.
+
+Create your container and add a label in the form `$APPNAME.cron.schedule="* * * * *"`, where the value is a valid cron expression (See the section [Cron Expression Formatting](#cron-expression-formatting)).
+
+$APPNAME will now start that container peridically on the schedule.
+
+### Cron Expression Formatting
+
+For more information on the cron expression parsing, see the docs for [robfig/cron](https://godoc.org/github.com/robfig/cron).
+
+## Caveats
+
+$APPNAME is quite simple right now. It does not yet:
+
+* Issue any retries
+* Cancel hanging jobs
+
+I intend to keep it simple as well. It will likely never:
+
+* Provide any kind of alerting (check out [Minitor](https://git.iamthefij.com/IamTheFij/minitor))
+* Handle job dependencies
+
+Either use a separate tool in conjunction with $APPNAME, or use a more robust scheduler like Tron, or Chronos.