Fix heartbeats insertion.

Add OS and editor fields.
Introduce aggregations (not working yet).

utils/common.go

@@ -0,0 +1,24 @@
+package utils
+
+import (
+	"errors"
+	"regexp"
+	"time"
+)
+
+func ParseDate(date string) (time.Time, error) {
+	return time.Parse("2006-01-02 15:04:05", date)
+}
+
+func FormatDate(date time.Time) string {
+	return date.Format("2006-01-02 15:04:05")
+}
+
+func ParseUserAgent(ua string) (string, string, error) {
+	re := regexp.MustCompile(`^wakatime\/[\d+.]+\s\((\w+).*\)\s.+\s(\w+)\/.+$`)
+	groups := re.FindAllStringSubmatch(ua, -1)
+	if len(groups) == 0 || len(groups[0]) != 3 {
+		return "", "", errors.New("Failed to parse user agent string")
+	}
+	return groups[0][1], groups[0][2], nil
+}