feat(postgres): Add auto upgrade from pg 9.5 to 9.6 (#283)

install.sh

@@ -55,6 +55,26 @@ if [ "$RAM_AVAILABLE_IN_DOCKER" -lt "$MIN_RAM" ]; then
     exit -1
 fi
 
+# Very naively check whether there's an existing sentry-postgres volume and the PG version in it
+if [[ $(docker volume ls -q --filter name=sentry-postgres) && $(docker run --rm -v sentry-postgres:/db busybox cat /db/PG_VERSION 2>/dev/null) == "9.5" ]]; then
+    # If this is Postgres 9.5 data, start upgrading it to 9.6 in a new volume
+    docker run --rm \
+    -v sentry-postgres:/var/lib/postgresql/9.5/data \
+    -v sentry-postgres-new:/var/lib/postgresql/9.6/data \
+    tianon/postgres-upgrade:9.5-to-9.6
+
+    # Get rid of the old volume as we'll rename the new one to that
+    docker volume rm sentry-postgres
+    docker volume create --name sentry-postgres
+    # There's no rename volume in Docker so copy the contents from old to new name
+    # Also append the `host all all all trust` line as `tianon/postgres-upgrade:9.5-to-9.6`
+    # doesn't do that automatically.
+    docker run --rm -it -v sentry-postgres-new:/from -v sentry-postgres:/to alpine ash -c \
+     "cd /from ; cp -av . /to ; echo 'host all all all trust' >> /to/pg_hba.conf"
+    # Finally, remove the new old volume as we are all in sentry-postgres now
+    docker volume rm sentry-postgres-new
+fi
+
 echo ""
 ensure_file_from_example $SENTRY_CONFIG_PY
 ensure_file_from_example $SENTRY_CONFIG_YML