title: Django translation: add custom translation
body: <p>I have an application where users can fill a text field.
  I would like "try" to translate it if the string that the user entered is in the <code>.po</code> <em>translation files</em>. </p>
  
  <p>So in one of my detail views, I did something like:</p>
  
  <pre><code>class InterrogationDetailView(generic.DetailView):
      model = Interrogation
  
      def get_context_data(self, **kwargs):
          context = super(InterrogationDetailView, self)\
              .get_context_data(**kwargs)
          if self.object is not None:
              context[u'translated_word'] = {
                  u'description': _(self.object.description),
              }
          return context
  </code></pre>
  
  <p>That's nice, it seems to work. So it searches in the <code>.po</code> files. So I'd like to add sentences, or words on my own in those <code>.po</code> files. When I try to add one translation that is <em>not</em> in my source files, when I call <em>makemessages</em> I get them commented like:</p>
  
  <pre><code>#~ msgid "I'm a test"
  #~ msgstr "Godsmack - Cryin' like a b"
  </code></pre>
  
  <p>How to solve this? And if I'm not doing this the right way (I've read a lot about <a href="https://docs.djangoproject.com/en/1.8/topics/i18n/translation/" rel="noreferrer">django translation</a>), what is the way to go?</p>