Create a new discussion by submitting the support form

[ruKurz]

• The issue is sent to Assistify and creates a new discussion. The issue information is posted as first message in the discussion.
• This first message is sent by a bot user and refers the e-mail address entered by the user. The e-mail address is not used for any other aspects, since the identity is not validated.
• The parent channel of the discussion is determined by analyzing the content of the problem description (by a "keywords/channels matching table"). If the system is not able to infer a parent channel, a default parent channel is used.
• Optional the customer can add attachments, like screenshots, to the issue. This attachment should also be posted into Assistify when creating a new discussion.

[ruKurz]

this issue is now part of #1