Update rake docs to reflect change in folder structure

docs/Makefile

@@ -0,0 +1,7 @@
+
+.PHONY: html
+
+html:
+	@cd $(CURDIR)/data && make html
+	@cd $(CURDIR)/course_authors && make html
+	@cd $(CURDIR)/developers && make html

rakelib/docs.rake

@@ -3,6 +3,19 @@ require 'launchy'
 # --- Develop and public documentation ---
 desc "Invoke sphinx 'make build' to generate docs."
 task :builddocs, [:options] do |t, args|
+    if args.options == 'dev'
+        path = "docs/developer"
+    elsif args.options == 'author'
+        path = "docs/course_authors"
+    elsif args.options == 'data'
+        path = "docs/data"
+    else
+        path = "docs"
+    end
+
+    Dir.chdir(path) do
+        sh('make html')
+    end
     path = "docs"
 
     Dir.chdir(path) do
@@ -13,6 +26,15 @@ end
 desc "Show docs in browser (mac and ubuntu)."
 task :showdocs, [:options] do |t, args|
     path = "docs"
+    if args.options == 'dev'
+        path = "docs/developer"
+    elsif args.options == 'author'
+        path = "docs/course_authors"
+    elsif args.options == 'data'
+        path = "docs/data"
+    else
+        path = "docs"
+    end
 
     Launchy.open("#{path}/build/html/index.html")
 end