Update JOJ3 Configuration Schema

JOJ3-Configuration-Schema.md

@@ -57,13 +57,10 @@ It contains the part of the configuration that will be used globally for all ass
 
 `[files]` table: file configuration parameters:
 - `whitelist.patterns [array of string]`: patterns of files allowed in the repository
-- `whitelist.file [string]`: file containing student defined patterns of files. This option should not be
- enabled unless strictly necessary 
-- `required.files [array of string]`: files that are written by students and must be found in the
- repository
-- `immutable.files [array of string]`: list all files managed by TT that students are forbidden to
- modify
-- `whitelist.file [string]`: sha26sum of all immutable files
+- `whitelist.file [string]`: file containing student defined patterns of files. This option should not be enabled unless strictly necessary 
+- `required.files [array of string]`: files that are written by students and must be found in the repository
+- `immutable.files [array of string]`: list all files managed by TT that students are forbidden to modify
+- `immutable.hash [array of string]`: list all the hash (`sha256sum`) of the immutable files
 
 **Important:** 
 - it should never be possible to disable health check
@@ -84,7 +81,7 @@ max_size = 5 # repo max size in MB
 [files]
 whitelist.patterns = ["*.cpp", "*.c", "*.m", "*.md", "Makefile", "CMakelist.txt", ".gitea", "messenger.json"] # files/patterns which are not  forbidden
 immutable.files = [".gitignore", ".gitattributes", ".gitea/workflows/push.yaml"] # readonly files
-immutable.hash = "26a7c6e8af3a562feef511898321ac206bed26cca50b4bd5ca6e72dec776d86b" # hash of readonly files
+immutable.hash = ["hash1", "hash2", "hash3"] # hash of readonly files
 required.files = [ "Changelog.md", "Readme.md" ] # files that must be found
 ```