When customizing CONSUL, one of the most common actions is adding a new
field to a form.
This requires modifying the permitted/allowed parameters. However, in
most cases, the method returning these parameters returned an instance
of `ActionController::Parameters`, so adding more parameters to it
wasn't easy.
So customizing the code required copying the method returning those
parameters and adding the new ones. For example:
```
def something_params
params.require(:something).permit(
:one_consul_attribute,
:another_consul_attribute,
:my_custom_attribute
)
end
```
This meant that, if the `something_params` method changed in CONSUL, the
customization of this method had to be updated as well.
So we're extracting the logic returning the parameters to a method which
returns an array. Now this code can be customized without copying the
original method:
```
alias_method :consul_allowed_params, :allowed_params
def allowed_params
consul_allowed_params + [:my_custom_attribute]
end
```
