Laravel Eloquent Collection Tips

- Adding a column with constant value to existing collection:
```
$existing_col->map(function ($col) {
    $col['url'] = 'http://your.url/here';
    return $col;
});
```
- To add a field to each element of the collection:
```
foreach($collection as $c) { $c->{"field"} = '1234';}
```
- If update for a column doesn’t work, make sure the column name is added to the fillable array in the Model. If you do not want to mass update the column, do this instead:
```
$collection->col=value; $collection->save();
```
  No need to add to fillable then.