Add database driver and config module

Signed-off-by: Asai Neko <sugar@sne.moe>

data/drivers/postgres.go

@@ -0,0 +1,24 @@
+package drivers
+
+import (
+	"nixcn-cms/config"
+	"strings"
+
+	"gorm.io/driver/postgres"
+	"gorm.io/gorm"
+)
+
+func SplitHostPort(url string) (host, port string) {
+	if !strings.Contains(url, ":") {
+		return url, "5432"
+	}
+	split := strings.Split(url, ":")
+	return split[0], split[1]
+}
+
+func Postgres(dsn ExternalDSN) (*DBClient, error) {
+	host, port := SplitHostPort(dsn.Host)
+	conn := "host=" + host + " user=" + dsn.Username + " password=" + dsn.Password + " dbname=" + dsn.Name + " port=" + port + " sslmode=disable TimeZone=" + config.TZ()
+	db, err := gorm.Open(postgres.Open(conn), &gorm.Config{})
+	return &DBClient{db}, err
+}

data/drivers/types.go

@@ -0,0 +1,16 @@
+package drivers
+
+import (
+	"gorm.io/gorm"
+)
+
+type ExternalDSN struct {
+	Host     string
+	Name     string
+	Username string
+	Password string
+}
+
+type DBClient struct {
+	*gorm.DB
+}