Update Dockerfile

Add 'IJulia' package

Dockerfile

@@ -26,10 +26,11 @@ RUN chmod 1777 /opt/julia/logs
 # Note the line-continuation backslash ("\") at the end of each line so that
 # all packages are installed in one Julia invocation.
 RUN julia -e 'using Pkg; Pkg.add("CSV"); Pkg.add("DataFrames"); \
-        Pkg.add("FileIO"); Pkg.add("Gurobi"); \
+        Pkg.add("FileIO"); Pkg.add("Clp"); \
         Pkg.add("HiGHS"); Pkg.add("JuMP"); Pkg.add("Plots"); \
         Pkg.add("PrettyTables"); Pkg.add("Random"); \
         Pkg.add("Statistics"); Pkg.add("VegaLite"); \
+        Pkg.add("IJulia"); \
         Pkg.instantiate();'
 
 # Override command to disable running jupyter notebook at launch