Added shell completion cobra command

Makefile

@@ -6,6 +6,9 @@ help:
 build: ## Builds a local version of Monday from sources
 	go build -ldflags "-X main.Version=sources-$(shell git rev-parse --short=5 HEAD)" -o monday ./cmd && mv monday /usr/local/bin
 
+build-binary: ## Builds a single binary of Monday from sources
+	/usr/local/bin/go build -ldflags "-X main.Version=sources-$(shell git rev-parse --short=5 HEAD)" -o monday ./cmd
+
 generate-mocks: ## Generate mocks for tests
 	@echo "> generating mocks..."
 

cmd/completion.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var completionCmd = &cobra.Command{
+	Use: "completion SHELL",
+	Args: func(cmd *cobra.Command, args []string) error {
+		if len(args) != 1 {
+			return fmt.Errorf("requires 1 arg, found %d", len(args))
+		}
+		return cobra.OnlyValidArgs(cmd, args)
+	},
+	ValidArgs: []string{"bash", "zsh"},
+	Short:     "Outputs shell completion for the given shell (bash or zsh)",
+	Long:      "Outputs shell completion for the given shell (bash or zsh)",
+	Run:       completion,
+}
+
+func completion(cmd *cobra.Command, args []string) {
+	switch args[0] {
+	case "bash":
+		rootCmd(cmd).GenBashCompletion(os.Stdout)
+	case "zsh":
+		rootCmd(cmd).GenZshCompletion(os.Stdout)
+	}
+}
+
+func rootCmd(cmd *cobra.Command) *cobra.Command {
+	parent := cmd
+
+	for parent.HasParent() {
+		parent = parent.Parent()
+	}
+
+	return parent
+}

cmd/main.go

@@ -45,6 +45,7 @@ func main() {
 		},
 	}
 
+	rootCmd.AddCommand(completionCmd)
 	rootCmd.AddCommand(editCmd)
 	rootCmd.AddCommand(initCmd)
 	rootCmd.AddCommand(runCmd)