Add SRO::ReadWrite class to README.doc

- Also, I changed name from NGR to SRO
- My first bright idea was to use NGR, short for No Google Results
- I wanted a module name that was both short and uncommon
- This Google search turned up no results => "module NGR" ruby
- Then I realized that NGR was phonetically a really dumb idea
- So I changed the name to SRO
- I debated the wisdome of even adding this story to a Git commit
- But then I decided to live dangerously and/or give someone a laugh
Rename file