feat: replace config system with viper based system

allows for config settings to be easily set through ENV variables,
config files, or CLI flags

adds flag to run migration on web server start (fixes #29)

internal/commands/commands.go

@@ -2,7 +2,11 @@ package commands
 
 import (
 	"fmt"
+	"net/http"
+	"strings"
+
 	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
 )
 
 const TaskcafeConfDirEnvName = "TASKCAFE_CONFIG_DIR"
@@ -26,6 +30,7 @@ var commandError error
 var configDir string
 var verbose bool
 var noColor bool
+var cfgFile string
 
 var rootCmd = &cobra.Command{
 	Use:     "taskcafe",
@@ -33,6 +38,36 @@ var rootCmd = &cobra.Command{
 	Version: version,
 }
 
+var migration http.FileSystem
+
+func init() {
+	cobra.OnInitialize(initConfig)
+
+	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file path")
+	migration = http.Dir("./migrations")
+}
+
+func initConfig() {
+	if cfgFile != "" {
+		// Use config file from the flag.
+		viper.SetConfigFile(cfgFile)
+	} else {
+		// Search config in home directory with name ".cobra" (without extension).
+		viper.AddConfigPath("./conf")
+		viper.AddConfigPath(".")
+		viper.AddConfigPath("/etc/taskcafe")
+		viper.SetConfigName("taskcafe")
+	}
+
+	viper.SetEnvPrefix("TASKCAFE")
+	viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
+	viper.AutomaticEnv()
+
+	if err := viper.ReadInConfig(); err != nil {
+		panic(err)
+	}
+}
+
 func Execute() {
 	rootCmd.SetVersionTemplate(versionTemplate)
 	rootCmd.AddCommand(newWebCmd(), newMigrateCmd(), newTokenCmd())