/usr/local/bin/node not an executable

On Fedora:

```
exec: Failed to execute process '/usr/local/bin/slack-tui': The file specified the interpreter '/usr/local/bin/node', which is not an executable command.

```

It is good practice to use shebangs like this:

```bash
#!/usr/bin/env node
```

My node-executable is in `/usr/bin/node` (very common)  and this will make that work.