Fix foreign key row reporting and empty table checks

build-gemfile.sh

@@ -0,0 +1,10 @@
+#!/bin/bash -e
+
+docker run --rm -ti -u $( id -u ):$( id -g ) -v $PWD:/build -w /build ruby:2.3 \
+    bash -e -c '
+        echo Installing dependencies
+        gem install -g
+        echo Building gemfile
+        gem build csvlint.gemspec
+    '
+ls -lF *.gem