Adding or editing provisioning or partition templates is not possible as the
webinterface tells me that "template can't be blank".

Selecting a file or just plainly add text to the textarea doesn't solve the
issue.

2016-03-24T14:47:21 [app] [I] Completed 200 OK in 35.7ms (Views: 20.4ms | ActiveRecord: 1.6ms)
2016-03-24T14:47:58 [app] [I] Started POST "/templates/provisioning_templates/" for 192.168.122.1 at 2016-03-24 14:47:58 +0100
2016-03-24T14:47:58 [app] [I] Processing by ProvisioningTemplatesController#create as */*
2016-03-24T14:47:58 [app] [I]   Parameters: {"utf8"=>"✓", "authenticity_token"=>"1W2nmkOJR33gRxMmYy98xgvTHqi58rQi7QRn5DJTrH4=", 
"provisioning_template"=>{"name"=>"test123", "template"=>"", "audit_comment"=>"test audit comment", "snippet"=>"0", 
"template_kind_id"=>"1", "operatingsystem_ids"=>[""]}, "mode"=>"ruby", "keybinding"=>"Default"}
2016-03-24T14:47:58 [app] [I] Failed to save: Template can't be blank

As you can see above the template variable is empty.