github-header.rb

require 'rest_client'
 
params = {
  :path => "test.txt",
  :message => "Test Commit",
  :committer => {
    :name => "Kevin Clark",
    :email => "kevin@kevinclark.ca"
  },
  :content => "bXkgbmV3IGZpbGUgY29udGVudHM="
}
 
header = {
  :Authorization => "token <TOKEN>"
}
 
RestClient.put "https://api.github.com/repos/vernalkick/kevinclark/contents/test.txt", params, header

This gives me a

404 Resource Not Found: {"message":"Not Found","documentation_url":"https://developer.github.com/v3/repos/contents/"}