Merge #1057

1057: add Julia ecosystem doc section r=CarloLucibello a=CarloLucibello

Partially fixing #251,  related to the discussion in #1051 .

Not exactly a poem that I wrote here, maybe someone could suggest a better rephrasing. 
Suggestion for additional packages to add to the list also welcome

Co-authored-by: CarloLucibello <carlo.lucibello@gmail.com>

docs/make.jl

@@ -23,6 +23,7 @@ makedocs(modules=[Flux, NNlib],
                      "Training" => "training/training.md"],
                   "GPU Support" => "gpu.md",
                   "Saving & Loading" => "saving.md",
+                  "The Julia Ecosystem" => "ecosystem.md",
                   "Performance Tips" => "performance.md",
                   "Community" => "community.md"],
          format = Documenter.HTML(assets = ["assets/flux.css"],

docs/src/ecosystem.md

@@ -0,0 +1,21 @@
+# The Julia Ecosystem
+
+One of the main strengths of Julia lies in an ecosystem of packages 
+globally providing a rich and consistent user experience.
+
+This is a non-exhaustive list of Julia packages, nicely complementing `Flux` in typical
+machine learning and deep learning workflows:
+
+- [ArgParse.jl](https://github.com/carlobaldassi/ArgParse.jl): package for parsing command-line arguments to Julia programs.
+- [Augmentor.jl](https://github.com/Evizero/Augmentor.jl): a fast image augmentation library in Julia for machine learning.
+- [BSON.jl](https://github.com/JuliaIO/BSON.jl): package for working with the Binary JSON serialisation format
+- [DataFrames.jl](https://github.com/joshday/OnlineStats.jl): in-memory tabular data in Julia
+- [DrWatson.jl](https://github.com/JuliaDynamics/DrWatson.jl):  a scientific project assistant software
+- [MLDatasets.jl](https://github.com/JuliaML/MLDatasets.jl): utility package for accessing common machine learning datasets
+- [OnlineStats.jl](https://github.com/joshday/OnlineStats.jl): single-pass algorithms for statistics
+- [Parameters.jl](https://github.com/mauro3/Parameters.jl): types with default field values, keyword constructors and (un-)pack macros
+- [ProgressMeters.jl](https://github.com/timholy/ProgressMeter.jl): progress meters for long-running computations
+- [TensorBoardLogger.jl](https://github.com/PhilipVinc/TensorBoardLogger.jl): easy peasy logging to [tensorboard](https://www.tensorflow.org/tensorboard) in Julia
+
+
+This tight integration among Julia pakages is shown in some of the examples in the [model-zoo](https://github.com/FluxML/model-zoo) repository.

docs/src/models/nnlib.md

@@ -1,4 +1,4 @@
-## NNlib
+# NNlib
 Flux re-exports all of the functions exported by the [NNlib](https://github.com/FluxML/NNlib.jl) package.
 
 ## Activation Functions