title: ForeignKey Field in django admin
body: <p>There are around 1.5 lakhs entry in User model. So when i am using it in django-admin without the raw_id_fields it is causing problem while loading all the entry as a select menu of foreign key.
  is there alternate way so that it could be loaded easily or could become searchable. </p>
  
  <p>Basically i have these models as of defined above and there is a User model which is used as ForeignKey in ProfileRecommendation models. so the database entry for user model consist of around 1,50,000 entries. I don't want default select option for these foreign fields. Instead if can filter them out and load only few entries of the user table. Or anyhow i can make them searchable like autocomplete suggestion</p>
  
  <h3>admin.py</h3>
  
  <pre><code>class ProfileRecommendationAdmin(admin.ModelAdmin):
      list_display = ('user', 'recommended_by', 'recommended_text')
      raw_id_fields = ("user", 'recommended_by')
      search_fields = ['user__username', 'recommended_by__username', ]
      admin.site.register(ProfileRecommendation, ProfileRecommendationAdmin)
  </code></pre>
  
  <h3>models.py</h3>
  
  <pre><code>class ProfileRecommendation(models.Model):
      user = models.ForeignKey(User, related_name='recommendations')
      recommended_by = models.ForeignKey(User, related_name='recommended')
      recommended_on = models.DateTimeField(auto_now_add=True, null=True)
      recommended_text = models.TextField(default='')
  </code></pre>