Deploy SQL schema from Cloud Build (#350)

Defined Docker image for schema deployment.

Included schema deploymer docker in the Cloud Build release process.

Defined Cloud Build config for schema deployment.

TESTED=Used cloud-build-local to test deployment flow
TESTED=Used docker to test schema deployer image in more ways

release/schema-deployer/Dockerfile

@@ -0,0 +1,56 @@
+# Copyright 2019 The Nomulus Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This Dockerfile builds an image that can be used in Google Cloud Build.
+# We need the following programs to build the schema deployer:
+# 1. Bash to execute a shell script.
+# 2. Java 8 for running the Flywaydb commandline tool.
+# 2. Cloud SQL proxy for connection to the SQL instance.
+# 3. The Flywaydb commandline tool.
+#
+# Please refer to deploy_sql_schema.sh for expected volumes and arguments.
+
+# Although any Linux-based Java image with bash would work (e.g., openjdk:8),
+# as a GCP application we prefer to start with a GCP-approved base image.
+FROM marketplace.gcr.io/google/ubuntu1804
+ENV DEBIAN_FRONTEND=noninteractive LANG=en_US.UTF-8
+# Install openjdk-8
+RUN apt-get update -y \
+    && apt-get install locales -y \
+    && locale-gen en_US.UTF-8 \
+    && apt-get install apt-utils -y \
+    && apt-get upgrade -y \
+    && apt-get install openjdk-8-jdk-headless -y
+
+# Get netstat, used for checking Cloud SQL proxy readiness.
+RUN apt-get install net-tools
+
+COPY deploy_sql_schema.sh /usr/local/bin/
+ADD https://dl.google.com/cloudsql/cloud_sql_proxy.linux.amd64 \
+    /usr/local/bin/cloud_sql_proxy
+RUN chmod +x /usr/local/bin/cloud_sql_proxy
+# Adapted from https://github.com/flyway/flyway-docker/blob/master/Dockerfile
+RUN \
+  FLYWAY_MAVEN=https://repo1.maven.org/maven2/org/flywaydb/flyway-commandline \
+  && FLYWAY_VERSION=$(curl ${FLYWAY_MAVEN}/maven-metadata.xml \
+                       | grep -oP "<release>\K.*(?=</release>)") \
+  && echo "Downloading Flyway-commandline-${FLYWAY_VERSION}" \
+  && mkdir -p /flyway \
+  && curl -L ${FLYWAY_MAVEN}/${FLYWAY_VERSION}/flyway-commandline-${FLYWAY_VERSION}.tar.gz \
+     -o flyway-commandline-${FLYWAY_VERSION}.tar.gz \
+  && tar -xzf flyway-commandline-${FLYWAY_VERSION}.tar.gz --strip-components=1 \
+       -C /flyway \
+  && rm flyway-commandline-${FLYWAY_VERSION}.tar.gz
+
+ENTRYPOINT [ "deploy_sql_schema.sh" ]