Please check out the instructure-bridge/homebrew-tap repository for the taps previously found in this repository!
brew install instructure-bridge/truss-cli/truss-cli
Or brew tap instructure-bridge/truss-cli and then brew install truss-cli.
Or install via URL (which will not receive updates):
brew install https://raw.githubusercontent.com/instructure-bridge/homebrew-truss-cli/master/Formula/truss-cli.rb
brew help, man brew or check Homebrew's documentation.