gitignore some non-essential files

[BarkleyBG]

Files that should be ignored (from #25):

• .vs/*.json (two files)
• .vs/codeformilwaukee.github.io/config/*.config
• .vs/codeformilwaukee.github.io/v16/.suo
• .vs/slnx.sqlite

I think this could be done by adding the following files to .gitignore:

• .vs/*

Should we ignore Gemfile.lock? See this: https://stackoverflow.com/questions/4151495/should-gemfile-lock-be-included-in-gitignore