Make todo example bootstrapping more resilient.

examples/todo/bootstrap.sh

@@ -4,6 +4,9 @@ SCRIPT_PATH=$(cd "$(dirname "$0")" ; pwd -P)
 DATABASE_URL=${SCRIPT_PATH}/db/db.sql
 
 pushd $SCRIPT_PATH > /dev/null
+  # clear an existing database
+  rm -f $DATABASE_URL
+
   # install the diesel CLI tools if they're not installed
   if ! command -v diesel >/dev/null 2>&1; then
     cargo install diesel_cli > /dev/null