Add support for -f flag

- If passed, passes to docker-compose as -f flag
- Supports multiple docker-compose files

main.go

@@ -23,6 +23,7 @@ var (
 
 	configFlag    = false
 	debuggingFlag = false
+	composeFiles  []string
 )
 
 func main() {
@@ -33,6 +34,7 @@ func main() {
 
 	flaggy.Bool(&configFlag, "c", "config", "Print the current default config")
 	flaggy.Bool(&debuggingFlag, "d", "debug", "a boolean")
+	flaggy.StringSlice(&composeFiles, "f", "file", "Specify alternate compose files")
 	flaggy.SetVersion(fmt.Sprintf("commit=%s, build date=%s, build source=%s, version=%s, os=%s, arch=%s\n", commit, date, buildSource, version, runtime.GOOS, runtime.GOARCH))
 
 	flaggy.Parse()
@@ -44,7 +46,7 @@ func main() {
 		os.Exit(0)
 	}
 
-	appConfig, err := config.NewAppConfig("lazydocker", version, commit, date, buildSource, debuggingFlag)
+	appConfig, err := config.NewAppConfig("lazydocker", version, commit, date, buildSource, debuggingFlag, composeFiles)
 	if err != nil {
 		log.Fatal(err.Error())
 	}

pkg/config/app_config.go

@@ -16,6 +16,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	yaml "github.com/jesseduffield/yaml"
@@ -364,7 +365,7 @@ type AppConfig struct {
 }
 
 // NewAppConfig makes a new app config
-func NewAppConfig(name, version, commit, date string, buildSource string, debuggingFlag bool) (*AppConfig, error) {
+func NewAppConfig(name, version, commit, date string, buildSource string, debuggingFlag bool, composeFiles []string) (*AppConfig, error) {
 	configDir, err := findOrCreateConfigDir(name)
 	if err != nil {
 		return nil, err
@@ -375,6 +376,11 @@ func NewAppConfig(name, version, commit, date string, buildSource string, debugg
 		return nil, err
 	}
 
+	// Pass compose files as individual -f flags to docker-compose
+	if len(composeFiles) > 0 {
+		userConfig.CommandTemplates.DockerCompose += " -f " + strings.Join(composeFiles, " -f ")
+	}
+
 	appConfig := &AppConfig{
 		Name:        name,
 		Version:     version,