HOWTO.md: added.

HOWTO.md

@@ -0,0 +1,39 @@
+# How-to
+
+This repo is structured the following way:
+
+- `${ODOO_VERSION}/`
+  - `base/`
+    - `Dockerfile`: file to build the `${ODOO_VERSION}-base` container image
+  - `${ODOO_RELEASE}/`
+    - `Dockerfile`: file to build the `${ODOO_VERSION}.${ODOO_RELEASE}` container image taking `${ODOO_VERSION}-base` as a base
+
+This repo contains a few bash scripts to
+help you generate docker container images.
+
+`generate.sh` will read the `${ODOO_VERSION}/releases.txt` file,
+parse the `release:checksum` lines and
+generate the `${ODOO_VERSION}/${ODOO_RELEASE}/Dockerfile`.
+
+```bash
+$ bash generate.sh
+```
+
+`build.sh` is used to build the docker container images locally.
+
+```bash
+$ bash build.sh
+```
+
+There are some auxiliary bash scripts to run docker container locally.
+
+```bash
+# start an Odoo release container
+$ bash start_container.sh 9.0 20161123
+
+# open interactive session on the Odoo container
+$ bash login.sh 9.0 20161123
+
+# stop and destroy
+$ bash stop_container.sh 9.0 20161123
+```