Write unit tests for missing endpoints

[carlobortolan]

Write specs for:

• POST:/api/v0/user/image
• PATCH:/api/v0/user
• POST:/api/v0/user/preferences
• PATCH:/api/v0/user/preferences
• POST:/api/v0/jobs
• PATCH:/api/v0/jobs
• POST:/api/v0/jobs/:id/applications
• GET:/api/v0/tokens
• POST:/api/v0/tokens
• PATCH:/api/v0/tokens/:id
• DELETE:/api/v0/tokens/:id
• GET:/api/v0/user/webhooks
• POST:/api/v0/user/webhooks/:source
• POST:/api/v0/webhooks/:source/:id
• GET:/api/v0/jobs/:id/application/pipeline
• GET:/api/v0/jobs/:id/applications/:id/pipeline

[github4touchdouble]

@carlobortolan still relevant???

[carlobortolan]

@carlobortolan still relevant???

Yes. If you want, feel free to implement some missing specs zo get our test coverage back to >90% (currently we're at 85%)