Add a .ledger file which is built by make examples (#445)

Having this file in place makes it harder to commit two examples with
the same prefix since it would cause a merge conflict in the ledger.

You can also build only the ledger by running `make ledger`

.github/workflows/build.yml

@@ -83,6 +83,24 @@ jobs:
             exit 1
           fi
 
+  check-ledger:
+    name: check ledger
+    runs-on: ubuntu-latest
+    steps:
+     - uses: actions/checkout@v4
+
+     - name: Generate ledger
+       run: |
+         make ledger
+
+     - name: Ensure ledger is up to date
+       run: |
+         if ! git diff --quiet; then
+           echo "generated ledger is out of date!"
+           echo "run 'make ledger' to regenerate the ledger"
+           exit 1
+         fi
+         
   dead-code-check:
     name: dead code check
     runs-on: ubuntu-latest

Makefile

@@ -25,7 +25,10 @@ generate: format
 lint:
 	golangci-lint --config=.golangci.yml run
 
-examples:
+ledger:
+	cd examples && ls > .ledger
+
+examples: ledger
 	@go build
 	@./pgroll init
 	@./pgroll bootstrap examples

examples/.ledger

@@ -0,0 +1,39 @@
+01_create_tables.json
+02_create_another_table.json
+03_add_column.json
+04_rename_table.json
+05_sql.json
+06_add_column_to_sql_table.json
+07_drop_table.json
+08_create_fruits_table.json
+09_drop_column.json
+10_create_index.json
+11_drop_index.json
+12_create_employees_table.json
+13_rename_column.json
+14_add_reviews_table.json
+15_set_column_unique.json
+16_set_nullable.json
+17_add_rating_column.json
+18_change_column_type.json
+19_create_orders_table.json
+20_create_posts_table.json
+21_add_foreign_key_constraint.json
+22_add_check_constraint.json
+23_drop_check_constraint.json
+24_drop_foreign_key_constraint.json
+25_add_table_with_check_constraint.json
+26_add_column_with_check_constraint.json
+27_drop_unique_constraint.json
+28_different_defaults.json
+29_set_replica_identity.json
+30_add_column_simple_up.json
+31_unset_not_null.json
+32_sql_on_complete.json
+33_rename_check_constraint.json
+34_create_events_table.json
+35_alter_column_multiple.json
+36_set_comment_to_null.json
+37_create_partial_index.json
+38_create_hash_index_with_fillfactor.json
+39_add_column_with_multiple_pk_in_table.json