update examples

src/lib.rs

@@ -6,14 +6,20 @@
 //!
 //! # Usage
 //! ```
-//! use obd2::{commands::Obd2DataRetrieval, device::Elm327, Obd2};
+//! use obd2::{commands::Obd2DataRetrieval, device::{Elm327, FTDIDevice}, Obd2};
 //!
 //! fn main() -> Result<(), obd2::Error> {
-//!     let mut device = Obd2::<Elm327>::default();
+//!     let mut device = Obd2::<Elm327::<FTDIDevice>>::new(Elm327::new(FTDIDevice::new()?)?)?;
 //!     println!("VIN: {}", device.get_vin()?);
 //!     Ok(())
 //! }
 //! ```
+//!
+//! alternatively, you could use a serial port provided by your operating system such as 
+//! /dev/ttyUSB0 on unix-like systems
+//! ```
+//! let mut device = Obd2::<Elm327::<SerialPort>>::new(Elm327::new(SerialPort::new("/dev/ttyUSB0")?)?)?;
+//! ```
 
 #![forbid(unsafe_code)]
 #![warn(missing_docs)]