add some example code

Author: ftl

README.md

@@ -9,6 +9,63 @@ To include `cabrillo` into your own projects as a library:
 ```shell
 go get github.com/ftl/cabrillo
 ```
+### Read a Cabrillo log file
+
+```go
+    f, err := os.Open("mycabrillo.log")
+    if err != nil {
+        panic(err)
+    }
+    log, err := cabrillo.Read(f)
+    if err != nil {
+        panic(err)
+    }
+```
+
+### Write a Cabrillo log file
+
+```go
+	log := cabrillo.NewLog()
+	log.Contest = "CQ-WW-CW"
+	log.Callsign = callsign.MustParse("DL0ABC")
+	log.Operators = []callsign.Callsign{callsign.MustParse("DL1ABC")}
+	log.Host = callsign.MustParse("DL1ABC")
+	log.Location = "DX"
+	log.Category.Operator = cabrillo.SingleOperator
+	log.Category.Assisted = cabrillo.Assisted
+	log.Category.Band = cabrillo.BandAll
+	log.Category.Power = cabrillo.HighPower
+	log.Category.Mode = cabrillo.ModeCW
+	log.Category.Transmitter = cabrillo.OneTransmitter
+	log.ClaimedScore = 12345
+	log.Club = "Bavarian Contest Club"
+	log.Name = "Hans Hamster"
+	log.Email = "[email protected]"
+	log.Address.Text = "Beispielstraße 1"
+	log.Address.City = "Musterstadt"
+	log.Address.Postalcode = "12345"
+	log.Address.StateProvince = "Bavaria"
+	log.Address.Country = "Germany"
+	log.CreatedBy = "Golang Cabrillo Example"
+	log.Soapbox = "this is just an example that shows how to write Cabrillo logs in Golang"
+
+    // qsos is where you keep your QSO data in your internal representation
+	qsoData := make([]QSO, 0, len(qsos)) 
+	for _, qso := range qsos {
+        // convertQSOToCabrillo converts your internal represenation to cabrillo.QSO
+		qsoData = append(qsoData, convertQSOToCabrillo(qso)) 
+	}
+	log.QSOData = qsoData
+
+    f, err := os.Create("mycabrillo.log")
+    if err != nil {
+        panic(err)
+    }
+	err = cabrillo.Write(f, log, false)
+    if err != nil {
+        panic(err)
+    }
+```
 
 ## License
 This software is published under the [MIT License](https://www.tldrlegal.com/l/mit).