Move default files, add navigation default

Signed-off-by: Knut Ahlers <knut@ahlers.me>

default_files/home.md

@@ -6,4 +6,6 @@ You've successfully started the software and entered the frontend. Now you can e
 
 When editing you can use [Markdown](https://en.wikipedia.org/wiki/Markdown) to style your contents. If you are familiar with it you should find everything as you are used to with one exception: Inside this Wiki you can link any [[Page]] using double brackets. Those will automatically get rewritten into internal links which have slightly different loading behaviour than external links. But even creating those will work just fine.
 
+To add links to the top navigation you can just edit the [[Navigation]] page and add them there. (Afterwards you need to reload once to refresh the navigation.)
+
 In case you experience trouble, have feature requests or feedback just visit the [Issue-Tracker](https://github.com/Luzifer/wiki/issues) on Github or take a look at the [Code](https://github.com/Luzifer/wiki).

default_files/navigation.md

@@ -0,0 +1,3 @@
+! Just list your page names for the navigation here
+! lines starting with an exclamation mark count as a
+! comment and will not be displayed

main.go

@@ -1,6 +1,6 @@
 package main
 
-//go:generate go-bindata -pkg $GOPACKAGE -o assets.go -modtime 1 -md5checksum ./frontend/... home.md
+//go:generate go-bindata -pkg $GOPACKAGE -o assets.go -modtime 1 -md5checksum ./frontend/... ./default_files/...
 
 import (
 	"bytes"
@@ -104,13 +104,14 @@ func handlePageRead(w http.ResponseWriter, r *http.Request) {
 		// All okay, render follows
 
 	case errFileNotFound:
-		if sanitizeFilename(vars["page"]) != "home.md" {
+		initContent, err := Asset(path.Join("default_files", sanitizeFilename(vars["page"])))
+		if err != nil {
 			http.Error(w, "Page not yet exists", http.StatusNotFound)
 			return
 		}
 
 		// Deliver initial "Home" page
-		file = &storedFile{Content: string(MustAsset("home.md"))}
+		file = &storedFile{Content: string(initContent)}
 
 	default:
 		http.Error(w, err.Error(), http.StatusInternalServerError)