[BUG] New Issue creates an error

[Hardenberg]

Is this a BUG REPORT or FEATURE REQUEST?:

• BUG
• FEATURE

What happened:

i'll try to create an new Issue:
http://localhost:8118/newissue
-> chrome: xxx:8118/api/v1/public/tickets/create 400 (Bad Request)
-> pm2:

3/15 11:22:16 [27243] - ^[[34mdebug^[[39m: message=accounts validation failed: role: Cast to ObjectID failed for value "user" at path "role", message=Cast to ObjectID failed for value "user" at path "ro$ at new ValidationError (/service/trudesk/node_modules/mongoose/lib/error/validation.js:30:11) at model.Document.invalidate (/service/trudesk/node_modules/mongoose/lib/document.js:2071:32) at model.$set (/service/trudesk/node_modules/mongoose/lib/document.js:1021:10) at model._handleIndex (/service/trudesk/node_modules/mongoose/lib/document.js:797:14) at model.$set (/service/trudesk/node_modules/mongoose/lib/document.js:743:22) at model.Document (/service/trudesk/node_modules/mongoose/lib/document.js:119:12) at model.Model (/service/trudesk/node_modules/mongoose/lib/model.js:93:12) at new model (/service/trudesk/node_modules/mongoose/lib/model.js:4503:13) at /service/trudesk/src/controllers/api/v1/tickets.js:442:16 at nextTask (/service/trudesk/node_modules/async/dist/async.js:5324:14) at Object.waterfall (/service/trudesk/node_modules/async/dist/async.js:5334:5) at apiTickets.createPublicTicket (/service/trudesk/src/controllers/api/v1/tickets.js:433:9) at Layer.handle [as handle_request] (/service/trudesk/node_modules/express/lib/router/layer.js:95:5) at next (/service/trudesk/node_modules/express/lib/router/route.js:137:13) at middleware.checkOrigin (/service/trudesk/src/middleware/middleware.js:167:10) at Layer.handle [as handle_request] (/service/trudesk/node_modules/express/lib/router/layer.js:95:5) at next (/service/trudesk/node_modules/express/lib/router/route.js:137:13) at middleware.checkCaptcha (/service/trudesk/src/middleware/middleware.js:147:10) at Layer.handle [as handle_request] (/service/trudesk/node_modules/express/lib/router/layer.js:95:5) at next (/service/trudesk/node_modules/express/lib/router/route.js:137:13) at Route.dispatch (/service/trudesk/node_modules/express/lib/router/route.js:112:3) at Layer.handle [as handle_request] (/service/trudesk/node_modules/express/lib/router/layer.js:95:5), name=ValidationError

What did you expect to happen:

A ticket from an external user should be created.

How to reproduce it (as minimally and precisely as possible):

-> create an Issue as unknown user

Anything else we need to know?:

Environment:

• Trudesk Version: 1.0.7
• OS (e.g. from /etc/os-release): debian 9
• Node.JS Version: 11.4
• MongoDB Version: 4.0.6
• Is this hosted on cloud.trudesk.io: no

[polonel]

Ref #167

[polonel]

Fixed in v1.0.8