Add modeltranslation support

[fabiocaccamo]

Steps to reproduce the problem:

• more languages, for example: en, it, fr
• default language: en
• modeltranslation installed
• model with a name field and a slug field populated from name
• name and slug fields are marked for translation in translation.py
• in the admin populate the name field for all languages using the different values and save it

Current result:
All slug values are always (for all languages) the slugified version of name in the default language:

slug_en populated from name_en
slug_it populated from name_en
slug_fr populated from name_en

Expected result:
Each slug value should be the slugified version of name for the corresponding language:

slug_en populated from name_en
slug_it populated from name_it
slug_fr populated from name_fr

Dirty solution overriding model save method:

#requires always_update = False
def save(self, *args, **kwargs):
    
    for lang_code, lang_verbose in settings.LANGUAGES:
        lang_code = lang_code.replace('-', '_')
        
        setattr(self, 'slug_%s' % lang_code, slugify( getattr(self, 'name_%s' % lang_code, u'') ))
        
    super( NameSlugModel, self ).save( *args, **kwargs )

[fabiocaccamo]

Check PR #26

[fabiocaccamo]

Any update about this issue?

[parruc]

+1 It would be really great to have such feature out of the box!!!

[fabiocaccamo]

@justinmayer @parruc still interested in a PR for this issue?

[parruc]

I have done it the ugly way in the save method so I do not strictly need it but I still think it would be beneficial for the project: urls are often based on slugs and having translated slugs that comes from specific language titles would helps with website positioning and user friendliness of the site IMO.

[fabiocaccamo]

@parruc I have the impression that this project is a little bit abandoned by the maintainer.