Issue

Server Setup Information:

• Did you test in newest Wekan?: Yes: Version 1.55.0
• For new Wekan install, did you configure root-url correctly https://github.com/wekan/wekan/wiki/Settings ? Yes, changed it to 127.0.0.1:80
• Wekan version: Version 1.55.0
• Operating System: Kubuntu 16.04
• Deployment Method(snap/docker/sandstorm/mongodb bundle/source): snap
• Http frontend if any (Caddy, Nginx, Apache, see config examples from Wekan GitHub wiki first): none

Problem description:

New cards cannot be found in swimlanes in certain circumstances:
New cards are assigned to Swimlane "General" on creation. If, however, this swimlane has been removed before, they don't show up in swimlane view.
If swimlane "General" is restored from trash, the new cards are available again.

I'd expect a behaviour, that

• Swimlane "General" should either be non-deletable or be replaced by an "unassigned" swimlane on deletion
• new cards should be assigned to "unassigned" or "general"
• existing cards should be moved to swimlane "general" or "unassigned" on deletion of their swimlane

Reproduction:
(tested in Firefox)

1. Set up a new board

2. enter a few cards on different lists

3. switch to swimlane view

4. create a few swimlanes and distribute the cards to the new lanes

5. delete swimlane "General"

6. switch to lists view

7. enter new card

8. switch to swimlane view
   ==> The new card can't be found.

9. restore "general" from trash
   ==> Card can be found in the restored swimlane