<!--- Please read this! Before opening a new issue, make sure to search for keywords in the issues filtered by the "T - Bug" label and verify the issue you're about to submit isn't a duplicate. ---> ### Summary Periods break the @ tag so tagging users with periods in their usernames is impossible. ### Steps to reproduce 1. Visit your channel 2. Type "@thefreethoughtproject.com" in a comment on one of your posts and hit enter. Additional commentary in Asana: https://app.asana.com/0/621013995005190/793533299158050 ### Platform information Chrome/Win10 ### What is the current *bug* behavior? The period breaks the @ tag so tagging users with periods in their usernames is impossible. ### What is the expected *correct* behavior? Either usernames with periods should not be allowed (and all current usernames with periods should have periods removed from their usernames) or users should be able to tag usernames with periods in them. I suggest the latter. ### Relevant logs and/or screenshots  ### Possible fixes (If you can, link to the line of code that might be responsible for the problem)