Do not allow users to create channels with a # (hashtag), it should automatically be added

Currently, users can create a channel that includes a # (hashtag), this is a problem because when the channel name with the hashtag (eg. #apple) appears on the left menu, it will display 2 hashtags like this: ##apple

To fix this issue:

1. When a user creates a channel, do not allow them to include hashtag. If they do include a hashtag or period
– show a notification that says “channel names can’t contain spaces and periods.
– do not allow them to save the channel

2. When user enters the channel name (when adding to a blueprint), user should not have to type in the # (hashtag), eg. if the channel name is #apple, user just needs to search for “apple” and not “#apple”