Support dedicated signup page in chorus mode

This adds a Sign Up link to site navigation and shows the
otherwise-landing page on /signup when in chorus mode.

Ref T681

app.go

@@ -213,6 +213,12 @@ func handleViewHome(app *App, w http.ResponseWriter, r *http.Request) error {
 		}
 	}
 
+	return handleViewLanding(app, w, r)
+}
+
+func handleViewLanding(app *App, w http.ResponseWriter, r *http.Request) error {
+	forceLanding := r.FormValue("landing") == "1"
+
 	p := struct {
 		page.StaticPage
 		Flashes []template.HTML

routes.go

@@ -150,6 +150,7 @@ func InitRoutes(apper Apper, r *mux.Router) *mux.Router {
 
 	// Handle special pages first
 	write.HandleFunc("/login", handler.Web(viewLogin, UserLevelNoneRequired))
+	write.HandleFunc("/signup", handler.Web(handleViewLanding, UserLevelNoneRequired))
 	write.HandleFunc("/invite/{code}", handler.Web(handleViewInvite, UserLevelNoneRequired)).Methods("GET")
 	// TODO: show a reader-specific 404 page if the function is disabled
 	write.HandleFunc("/read", handler.Web(viewLocalTimeline, UserLevelReader))

templates/base.tmpl

@@ -38,6 +38,7 @@
 				<nav class="tabs">
 					<a href="/about"{{if eq .Path "/about"}} class="selected"{{end}}>About</a>
 					{{if and (and (not .SingleUser) .LocalTimeline) .CanViewReader}}<a href="/read"{{if eq .Path "/read"}} class="selected"{{end}}>Reader</a>{{end}}
+					{{if and (and (and (not .SingleUser) .Chorus) .OpenRegistration) (not .Username)}}<a href="/signup"{{if eq .Path "/signup"}} class="selected"{{end}}>Sign up</a>{{end}}
 					{{if and (not .SingleUser) (not .Username)}}<a href="/login"{{if eq .Path "/login"}} class="selected"{{end}}>Log in</a>{{else if .SimpleNav}}<a href="/me/logout">Log out</a>{{end}}
 				</nav>
 				{{if .SimpleNav}}{{if .Username}}<div class="right-side" style="font-size: 0.86em;">

templates/user/include/header.tmpl

@@ -47,6 +47,7 @@
 				{{if .SimpleNav}}
 					<a href="/about">About</a>
 					{{if and (and (not .SingleUser) .LocalTimeline) .CanViewReader}}<a href="/read">Reader</a>{{end}}
+					{{if and (and (and (not .SingleUser) .Chorus) .OpenRegistration) (not .Username)}}<a href="/signup"{{if eq .Path "/signup"}} class="selected"{{end}}>Sign up</a>{{end}}
 					{{if .Username}}<a href="/me/logout">Log out</a>{{else}}<a href="/login">Log in</a>{{end}}
 				{{else}}
 					<a href="/me/c/"{{if eq .Path "/me/c/"}} class="selected"{{end}}>Blogs</a>