Interrapt G26

Description:
The name fields in Attendees menu should accepts only alphabetic characters and the special characters "." and "-". The name filed allows input of numbers.

Steps to reproduce:
1. Login on interrapt
2. Open Attendees form the sidebar
3. Click on create
4. In the name filed enter numbers (12345)
5. Fill out all the others fields
6. Click on create

Expected result
New attendee should not be created, the name filed should accepts only alphabetic characters, and should not accepts numbers. Message with red letters should appear telling the user that the name filed is required
Actual result
New attendee is created only with numbers