For instructions on how to keep Redmine user files synced with Dropbox, see this post.
To create a link to commit in the source code repository, use the first 12 digits of the hash!
To add source code syntax coloring, use the tags below. More information (link).
It is quite easy to integrate Redmine with Active Directory (or any LDAP service). What I found confusing was that the LDAP root is case-sensitive! Changing "dc=domain, dc=com" to "DC=domain, DC=com" made a whole lot of a difference between LDAP integration not working and working!
Documentation is here.