support scripts.dokku in app.json. closes #1824

tests/unit/10_core_1.bats

@@ -146,3 +146,24 @@ EOF
   echo "status: "$status
   assert_output "3001/udp 3000/tcp 3003"
 }
+
+@test "(core) app.json scripts" {
+  deploy_app
+
+  run /bin/bash -c "dokku run $TEST_APP ls /app/prebuild.test"
+  echo "output: "$output
+  echo "status: "$status
+  assert_failure
+
+  run /bin/bash -c "dokku run $TEST_APP ls /app/predeploy.test"
+  echo "output: "$output
+  echo "status: "$status
+  assert_success
+
+  CID=$(docker ps -a -q  -f "ancestor=dokku/${TEST_APP}" -f "label=dokku_phase_script=postdeploy")
+  IMAGE_ID=$(docker commit $CID dokku-test/${TEST_APP})
+  run /bin/bash -c "docker run -ti $IMAGE_ID ls /app/postdeploy.test"
+  echo "output: "$output
+  echo "status: "$status
+  assert_success
+}