Organize modules in new source files

+//
+// Move some restaurant stuff in a different file....
+//
+// Georg Hopp <georg@steffers.org>
+//
+// Copyright © 2019 Georg Hopp
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+pub mod hosting;
+
+mod serving {
+    fn take_order() {}
+    fn take_payment() {}
+}

+//
+// Now also sepatate hosting....
+//
+// Georg Hopp <georg@steffers.org>
+//
+// Copyright © 2019 Georg Hopp
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+pub fn add_to_waitlist() {}
+fn seat_at_table() {}

@@ -19,18 +19,7 @@
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //
 
-mod front_of_house {
-    pub mod hosting {
-        pub fn add_to_waitlist() {}
-        fn seat_at_table() {}
-    }
-
-    mod serving {
-        fn take_order() {}
-        fn take_payment() {}
-
-    }
-}
+mod front_of_house;
 
 fn serve_order() {}