Changes to Create a new event

the request property end_date became required

the request property name became required

the request property start_date became required

the request's body type changed from no type to object

the response's body type changed from no type to integer for status 200

the response's body type changed from no type to object for status 400

the response's body type changed from no type to object for status 409

added the new optional request property end_date

added the new optional request property name

added the new optional request property start_date

added the optional property message to the response with the 400 status

added the optional property message to the response with the 409 status