documentation of supported-by

systems/meta/README.md

@@ -15,8 +15,10 @@ Each post needs some specific parameters:
  * **end_date** (optional) the system end date (YYYY[-MM])
 
  * **people** (optional) a list of KWARC people involved in this
+ * **supported-by** (optional) a list projects that have provided funding that supports
+   this project. Use the file names of the project to reference them. 
  
  * **website** (optional): the system home page
  * **repository** (optional): the system repository
 
-A system is considered active, iff it has no end date. 
\ No newline at end of file
+A system is considered active, iff it has no end date.