fix the type of Job.container_id

(this is a docker container id, not a foreign key)

django/allgo/main/models.py

@@ -346,6 +346,7 @@ class Job(TimeStampModel):
     access_token = models.CharField(max_length=255, blank=True, null=True)
     state = models.IntegerField(choices=JOB_STATE_CHOICES, default=NEW)
     result = models.IntegerField(choices=JOB_RESULT_CHOICES, default=NONE)
+    container_id = models.CharField(max_length=64, null=True)   # docker container id
 
     # Relationships
     queue = models.ForeignKey(JobQueue, related_name="job_queue")
@@ -354,9 +355,6 @@ class Job(TimeStampModel):
 
     runner = models.ForeignKey(Runner, related_name="runner", blank=True, null=True)
 
-    # Not in use because I don't have any related table yet
-    container_id = models.IntegerField(blank=True, null=True)
-
     class Meta:
         db_table = 'dj_jobs'