What is the difference between the load and sync commands?

[gotjosh]

At the moment, it is unclear what is the exact difference between both commands. From a quick peek at the code it seems like load is more of a "only uploaded if the rule group does not exist under that namespace" while sync is more of a replace everything but tell me about it.

I'd be good to make clear how do we support each of the following use cases:

• Create or update a namespace/group/rule only if it doesn't exist
• Create or update a namespace/group/rule (regardless of its status)
• Find the difference (at each of namespace/group/rules) between the input file and what already exists on the server. Then delete or create whatever is missing.

[jtlisi]

Load is meant to create the rules provided if they don’t exist. Sync takes a set of rules files and ensures that the state of what is running in the ruler matches those files exactly

[coderalex]

This needs to be documented. Neither rules sync nor rules diff is mentioned in README.md