Create manpage for soledad-create-userdb script

Building packages fails at linting stage with:

W: soledad-server: binary-without-manpage usr/bin/create-user-db
N: 
N:    Each binary in /usr/bin, /usr/sbin, /bin, /sbin or /usr/games should
N:    have a manual page
N:    
N:    Note that though the man program has the capability to check for several
N:    program names in the NAMES section, each of these programs should have
N:    its own manual page (a symbolic link to the appropriate manual page is
N:    sufficient) because other manual page viewers such as xman or tkman
N:    don't support this.
N:    
N:    If the name of the man page differs from the binary by case, man may be
N:    able to find it anyway; however, it is still best practice to make the
N:    case of the man page match the case of the binary.
N:    
N:    If the man pages are provided by another package on which this package
N:    depends, lintian may not be able to determine that man pages are
N:    available. In this case, after confirming that all binaries do have man
N:    pages after this package and its dependencies are installed, please add
N:    a lintian override.
N:    
N:    Refer to Debian Policy Manual section 12.1 (Manual pages) for details.
N:    
N:    Severity: normal, Certainty: possible
N:    
N:    Check: manpages, Type: binary
N: