504 error when deleting a channel

[mmuller]

Found in version: d9a0609

Preconditions:

• There is a channel Ch1.

Steps to reproduce:

1. Navigate the Ch1 overview.
2. Click on Delete this channel.

Obtained result:

• A 504 error is thrown.

[matiasgarciaisaia]

We believe one of the preconditions is to have a great number of CallLogs, either associated with this particular channel or in the system at all (we have to check which of both is true).

The :dependent => :nullify or :dependent => :destroy must be taking long enough that Rancher's proxy returns a 504 instead while Verboice keeps destroying stuff. We should probably move the channel deletion to a asynchronous job.