Suggested changes to allow opening database from byte slice

reader.go

@@ -5,7 +5,7 @@
 package geoip2
 
 import (
-"github.com/oschwald/maxminddb-golang"
+"github.com/oxtoacart/maxminddb-golang"
 "net"
 )
 
@@ -29,7 +29,7 @@ type City struct {
 Location struct {
 Latitude float64
 Longitude float64
-MetroCode int  `maxminddb:"metro_code"`
+MetroCode string `maxminddb:"metro_code"`
 TimeZone string `maxminddb:"time_zone"`
 }
 Postal struct {
@@ -101,6 +101,14 @@ func Open(file string) (*Reader, error) {
 return &Reader{mmdbReader: reader}, err
 }
 
+// OpenBytes takes a string path to a file and returns a Reader structure or an
+// error. The database file opened using a memory map. Use the Close method
+// on the Reader object to return the resources to the system.
+func OpenBytes(bytes []byte) (*Reader, error) {
+reader, err := maxminddb.OpenBytes(bytes)
+return &Reader{mmdbReader: reader}, err
+}
+
 // City takes an IP address as a net.IP struct and returns a City struct
 // and/or an error. Although this can be used with other databases, this
 // method generally should be used with the GeoIP2 or GeoLite2 City databases.