Using a '#' (hastag) not working in a tag.

[MeesvanStraten]

Describe the bug
Currently the '#' is ignored on the backend. When searching for tags the # is completly ignored. The usability tests gave us insight that some users are thinking of using a # in a tag.

To Reproduce
Steps to reproduce the behavior:

1. Add a project with a # in the tag.
2. Search for the project using the hashtag. Using the # does not make a difference and the search query ignores the #.

Expected behavior
Working with # to be supported.