You have a few options:

1. Paired programming. Have the people who don't understand the tech pair with the people who do. Might slow your velocity down a bit, but it's more effective than writing reams of documentation.
2. Consult with the product owner, what are the criteria for acceptance that the product owner has established. Perhaps the product owner is unaware that this individual is spending project cycles on this.
3. Write good x-unit tests. Well written tests should provide ample documentation for the system being written.
4. Provide them with the Stack Exchange url ;)

Cheers!

You have a few options:

1. Paired programming. Have the people who don't understand the tech pair with the people who do. Might slow your velocity down a bit, but it's more effective than writing reams of documentation.
2. Consult with the product owner, what are the criteria for acceptance that the product owner has established. Perhaps the product owner is unaware that this individual is spending project cycles on this.
3. Write good x-unit tests. Well written tests should provide ample documentation for the system being written.
4. Provide them with the Stack Exchange url ;)

Documentation that is truly necessary emerges, it is not the result of a contrived, forced effort.

Cheers!