feature: add replacer for ENV vars

cmd/root.go

@@ -3,6 +3,7 @@ package cmd
 import (
 	"fmt"
 	"os"
+	"strings"
 
 	"codeberg.org/vlbeaudoin/serpents"
 	"github.com/spf13/cobra"
@@ -138,6 +139,8 @@ func initConfig() {
 		viper.SetConfigName(".bottin-agenda")
 	}
 
+	viper.SetEnvPrefix("BOTTINAGENDA")
+	viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
 	viper.AutomaticEnv() // read in environment variables that match
 
 	// If a config file is found, read it in.