It interfaces to a number of solvers, both commercial and open source. According to this page [1] it currently supports:

COIN Cbc/Clp, GNU GLPK, Gurobi, Ipopt, Mosek, NLopt

So you can use it to generate models that are solved in Gurobi if you want. Or you can use the available open source solvers.

[1] http://www.juliaopt.org/