Move database configuration into config file

Also support mysql and postgres (at least in name, they haven't been
fully tested yet)

config.go

@@ -1,20 +1,75 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"gopkg.in/gcfg.v1"
+	"strings"
 )
 
-type Config struct {
-	MoneyGo struct {
-		Fcgi           bool   // whether to serve FCGI (HTTP by default if false)
-		Base_directory string // base directory for serving files out of
-		Port           int    // port to serve API/files on
+type DbType uint
+
+const (
+	SQLite DbType = 1 + iota
+	MySQL
+	Postgres
+)
+
+var dbTypes = [...]string{"sqlite3", "mysql", "postgres"}
+
+func (e DbType) Valid() bool {
+	// This check is mostly out of paranoia, ensuring e != 0 should be
+	// sufficient
+	return e >= SQLite && e <= Postgres
+}
+
+func (e DbType) String() string {
+	if e.Valid() {
+		return dbTypes[e-1]
 	}
+	return fmt.Sprintf("invalid DbType (%d)", e)
+}
+
+func (e *DbType) FromString(in string) error {
+	value := strings.TrimSpace(in)
+
+	for i, s := range dbTypes {
+		if s == value {
+			*e = DbType(i + 1)
+			return nil
+		}
+	}
+	*e = 0
+	return errors.New("Invalid DbType: \"" + in + "\"")
+}
+
+func (e *DbType) UnmarshalText(text []byte) error {
+	return e.FromString(string(text))
+}
+
+type MoneyGo struct {
+	Fcgi    bool   // whether to serve FCGI (HTTP by default if false)
+	Port    int    // port to serve API/files on
+	Basedir string `gcfg:"base-directory"` // base directory for serving files out of
+	DBType  DbType `gcfg:"db-type"`        // Whether this is a sqlite/mysql/postgresql database
+	DSN     string `gcfg:"db-dsn"`         // 'Data Source Name' for database connection
+}
+
+type Config struct {
+	MoneyGo MoneyGo
 }
 
 func readConfig(filename string) (*Config, error) {
-	var cfg Config
+	cfg := Config{
+		MoneyGo: MoneyGo{
+			Fcgi:    false,
+			Port:    80,
+			Basedir: "src/github.com/aclindsa/moneygo/",
+			DBType:  SQLite,
+			DSN:     "file:moneygo.sqlite?cache=shared&mode=rwc",
+		},
+	}
+
 	err := gcfg.ReadFileInto(&cfg, filename)
 	if err != nil {
 		return nil, fmt.Errorf("Failed to parse config file: %s", err)