Add cobra root command

cmd/root.go

@@ -0,0 +1,19 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var RootCmd = &cobra.Command{
+	Use:   "campaigner",
+	Short: "Create and manage Open Source campaigns",
+}
+
+func Execute() {
+	if err := RootCmd.Execute(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+	}
+}