Security and users table updates

• Update: Added new migration file for users table updates
• Update: Added new validation helper
• Update: Added new hash helper
• Update: Updated md5 password scheme to something more secure. See hash_helper.generateHash.
• Update: Various Updates to update code to new column names for users table.
• Update: Fix to display group invites.
• Update: Fix of homepage display for users having no groups defined.