Remove presence: true from password validation
Add migration for mentions
Add Mention model
Add migration for leader_follower join model
Add LeaderFollower model
Add index action
Add routes for users controller
Add index view for users and display usernames of all users
Remove turbolinks
Render navigation partial
Add link to users show page
Put @ inside link
Add header partial
Render header from shared header partial
Add show action
Render header from shared header partial
Show all the user's statuses
Add helper for formatting datetimes
Add display_datetime helper for created_at
Refine formatting for datetime display helper