Add summary pages for hosted notebooks

docs/make_notebook_index.jl

@@ -0,0 +1,26 @@
+using Markdown
+
+cd("src/notebooks/") do
+    contents =
+        map(readdir() |> filter(!=(".gitignore")) |> filter(!=("index.html"))) do file
+            last_updated = let
+                cmdout =
+                    read(`git log $file`, String) |>
+                    IOBuffer |>
+                    eachline |>
+                    Iterators.Stateful
+                @assert popfirst!(cmdout) |> startswith("commit")
+                @assert popfirst!(cmdout) |> startswith("Author")
+                dateline = popfirst!(cmdout)
+                chopprefix(dateline, "Date:") |> strip
+            end
+            "- [`$file`]($file) (last updated: $last_updated)"
+        end |> (v -> join(v, '\n'))
+    index_content = Markdown.parse("""
+    # notebooks
+    $(contents)
+    """)
+    open("index.html", "w") do f
+        show(f, MIME"text/html"(), index_content)
+    end
+end

docs/src/notebooks/.gitignore

@@ -0,0 +1 @@
+index.html