undid regressions from code merge with diego

history/models.py

@@ -7,7 +7,7 @@ class HistorySync(models.Model):
     Keeps an historic record of the importation of products for a company
     """
 
-    company = models.ForeignKey('companies.Company', on_delete=models.DO_NOTHING, null=True, related_name='history_company')
+    company = models.ForeignKey('companies.Company', on_delete=models.DO_NOTHING, null=True)
     rss_url = models.URLField('URL del feed', null=True, blank=True)
     sync_date = models.DateTimeField('Fecha de lanzamiento', null=True)
     result = models.TextField('Resultado', null=True, blank=True)