Error: Bad Interpreter

After installing, the following error occurs when trying to run `tableify`:

```bash
⇒  tableify 
bash: /usr/local/bin/tableify: /usr/bin/node: bad interpreter: No such file or directory
```

Fixed this by correcting the she-bang in the script i.e. "/usr/bin/env node"

Some more changes:
* renamed the script to a more CLI friendly format
* added a `.gitignore` to ignore locally installed node modules i.e. node_modules directory