curl -H 'Authorization: Basic ENCODED_CLIENT_CREDENTIALS' --data 'username=user@test.com&password=test&grant_type=password&scope=user%20documents%20user%2Fdocumentsv2' https://api.com/oauth2/token

access = RestClient::Request.new(
        :method => :post,
        :url => 'https://api.com/oauth2/token',
        :data => {
            :username => 'xxxx',
            :password => 'xxxx',
            :grant_type => 'password'
        },
        :headers => {
            :Authorization => "Basic some_string",
            :'Content-Type' => 'application/x-www-form-urlencoded'
        }
    )