Add csv.dbscheme to tutorial lib

The setup script will copy this from the DB.
However, committing the file makes local query testing
easier even without running the setup script.

Author: adityasharad

tutorial-lib/csv.dbscheme

@@ -1,3 +1,12 @@
-/*
- * This file is deliberately empty and will be replaced at startup.
- */
+/** External data **/
+
+externalData(
+  int id : @externalDataElement,
+  varchar(900) path : string ref,
+  int column: int ref,
+  varchar(900) value : string ref
+);
+
+sourceLocationPrefix(
+  string prefix : string ref
+);

tutorial-queries/tutorial.ql

@@ -1,8 +1,8 @@
+// Write your first CodeQL query here!
+
 // Import the tutorial library.
 // See https://codeql.github.com/docs/writing-codeql-queries/ql-tutorials/#ql-tutorials.
 import tutorial
 
-// Write your first CodeQL query here!
-
 from Person p
 select p