Merge pull request #937 from SciML/add_warning_to_rs_fields_set

Add warning to ReactionSystem field list

Author: TorkelE

src/reactionsystem.jl

@@ -204,6 +204,14 @@ end
 
 ### ReactionSystem Structure ###
 
+""" 
+WARNING!!!
+
+The following variable is used to check that code that should be updated when the `ReactionSystem` 
+fields are updated has in fact been updated. Do not just blindly update this without first checking 
+all such code and updating it appropriately (e.g. serialization). Please use a search for
+`reactionsystem_fields` throughout the package to ensure all places which should be updated, are updated.
+"""
 # Constant storing all reaction system fields (in order). Used to check whether the `ReactionSystem`
 # structure have been updated (in the `reactionsystem_uptodate_check` function).
 const reactionsystem_fields = (