Documentation stanza needs StatsBase

Author: dmbates

.travis.yml

@@ -19,7 +19,7 @@ jobs:
       julia: 1.0
       os: linux
       script:
-        - julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
+        - julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate(); Pkg.add("StatsBase")'
         - julia --project=docs/ docs/make.jl
       after_success: skip
 notifications: