Update JOJ3 Configuration Schema

JOJ3-Configuration-Schema.md

@@ -2,11 +2,15 @@
 
 *Goals:* simple configuration files, which can easily be manually edited by TAs.  These files are then parsed by joj-config-generation script to generate final internal `json` configurations files and joj3 to find the `json` config files.
 
+Levels:
+- repo: repository 
+- assignment: homework or project
+- task: exercise or milestone
+
 ## Repo level
 
 Teaching team info, eg. useful to check who triggered a grading.
 
-It should never be possible to disable health check. 
 
 Health check configuration:
 - required files (readme, changelog)
@@ -15,8 +19,21 @@ Health check configuration:
 - immutable files (gitignore, workflows)
 - repo size limit
 
+**Important:** it should never be possible to disable health check.
+
+
 ## Task level
 
+Basic idea: 
+- list all stages that are to be run
+- provide config for each stage
+- various code quality tools can be used, but they all feature: 
+  - a command
+  - a list of tests
+  - a weight for each test
+- joj sets a default score and cpu/mem limits
+- test cases can be individually configured if necessary
+
 ```toml
 stages = [ "compile", "code_quality", "joj" ]