gem install oauth
irb
consumer = ::OAuth::Consumer.new(
"OAUTH_KEY",
"OAUTH_SECRET",
:site=>"https://www.readability.com/",
:access_token_path => "/api/rest/v1/oauth/access_token/"
)
consumer.get_access_token(nil, {}, {
:x_auth_mode =>'client_auth',
:x_auth_username => "USERNAME",
:x_auth_password => "PASSWORD"
})