diff --git a/arkindex/training/migrations/0001_initial.py b/arkindex/training/migrations/0001_initial.py
index 56ad1bc37d92ed6b2855979b3b2aa04f6a1c291a..78d021245377de7202bbc896a3239981d4506b61 100644
--- a/arkindex/training/migrations/0001_initial.py
+++ b/arkindex/training/migrations/0001_initial.py
@@ -51,9 +51,9 @@ class Migration(migrations.Migration):
                 ('created', models.DateTimeField(auto_now_add=True)),
                 ('updated', models.DateTimeField(auto_now=True)),
                 ('name', models.CharField(max_length=100, unique=True)),
-                ('description', models.TextField(default='')),
+                ('description', models.TextField(default='', blank=True)),
                 ('public', models.BooleanField(default=False)),
-                ('compatible_workers', models.ManyToManyField(related_name='models', to='process.worker')),
+                ('compatible_workers', models.ManyToManyField(related_name='models', to='process.worker', blank=True)),
             ],
             options={
                 'abstract': False,
diff --git a/arkindex/training/models.py b/arkindex/training/models.py
index b0d57aeff78be1b3b67bfae95c2191103fc0974e..9f36caea539b5ffe9d02db02cf83418e82c2b2ba 100644
--- a/arkindex/training/models.py
+++ b/arkindex/training/models.py
@@ -26,12 +26,12 @@ class Model(IndexableModel):
     # Name of the model, unique
     name = models.CharField(max_length=100, unique=True)
 
-    description = models.TextField(default="")
+    description = models.TextField(default="", blank=True)
 
     public = models.BooleanField(default=False)
 
     # Link to the workers that are able to use this model
-    compatible_workers = models.ManyToManyField('process.Worker', related_name='models')
+    compatible_workers = models.ManyToManyField('process.Worker', related_name='models', blank=True)
 
     # Memberships to handle access rights on models
     memberships = GenericRelation('users.Right', 'content_id')