Provide a way to create polls with either single or multiple options to vote

[evalica]

Currently, when creating a poll, the voters can select all the options, since the control used are checkboxes.
There are several cases when the creator of the poll wants to limit the voters to a single choice. This could be implemented by using radio controls instead.

Current:

Expected:

Proposal:

[evalica]

ideally this option needs to be flexible. Users might change their mind and switch between options multiple times, or sometimes even if there are already votes given.