Add url param to login form to control redirect

Site layouts that include a login form on every page can now include
their relative URI (`request.path`) so the user can be redirected back
to the same page after login.

rophako/modules/account.py

@@ -34,6 +34,12 @@ def login():
             session["uid"]  = db["uid"]
             session["name"] = db["name"]
             session["role"] = db["role"]
+
+            # Redirect them to a local page?
+            url = request.form.get("url", "")
+            if url[0] == "/":
+                return redirect(url)
+
             return redirect(url_for("index"))
         else:
             flash("Authentication failed.")