Updated "Building MicroStack" section of CONTRIBUTING.md

Now reflects current build process, and has correct url to source code.

Also changed references to "microstack" and "Microstack" to
"MicroStack".

Change-Id: I60f6a28c3e47ed785692e59c0de79e298e437900
Closes-Bug: 1846979

CONTRIBUTING.md

@@ -1,58 +1,87 @@
 # Contributing
 
-## Building Microstack
+## Building MicroStack
 
-Currently, you must build microstack on a machine running Ubuntu 16.04 Xenial. A goal of the project is to expand this to other environments, but for now, there are some Debian packages specific to Xenial required in snapcraft.yaml.
+MicroStack builds are tested on an Ubuntu 18.04 LTS machine with 16G
+of RAM, two cpu cores, and 50G of free disk space. You should be able
+to build MicroStack on any machine matching those minimum specs, as
+long as it is capable of running bash and snapd. If you run into any
+snags doing so, please file bugs at
+https://bugs.launchpad.net/microstack
 
-To build microstack, do the following:
+To build MicroStack on a capable machine, run:
 
-```
-export PATH=/snap/bin:$PATH
-sudo snap install --classic snapcraft
-git clone git@github.com:CanonicalLtd/microstack.git
-cd microstack
-snapcraft
-```
+    git clone https://opendev.org/x/microstack.git
+    cd microstack
+    tox
 
-Optionally, if you want to keep the system clean of dependencies, you can install lxd and do a cleanbuild (note that the apt packaged version of lxd in Xenial won't work -- you want to use the snap).
+This will run tools/multipass_build.sh, which installs some
+dependencies on your system, and then run some tests. If you want to
+have more control over the build process and installed dependencies,
+replace the tox line with:
 
-```
-sudo snap install --classic lxd
-sudo usermod -aG lxd <your username>
-newgrp lxd
-lxd init  # Going with the defaults is fine
-```
+    snapcraft
 
-Then replace `snapcraft` above with `snapcraft cleanbuild`
+or
 
-## How the Code is Structured
+    snapcraft --use-lxd
 
-Microstack is a Snap, which means that, after it has been built, it contains all the code and dependencies that it needs, destined to be mounted in a read only file system on a host.
+(You may have to install snapcraft and lxd or multipass on your system
+first if you go this route -- inspect tools/multipass_build.sh and
+tools/lxd_build.sh for tips.)
 
-Before contributing, you probably want to read the general Snap Documentation here: https://docs.snapcraft.io/snap-documentation/3781
+## How the code is structured
 
-There are several important files and directories in microstack, some of which are like those in other snaps, some of which are unique to microstack:
+MicroStack is a Snap, which means that, after it has been built, it
+contains all the code and dependencies that it needs, destined to be
+mounted in a read only file system on a host.
 
-### `./snapcraft.yaml`
+Before contributing, you probably want to read the general Snap
+Documentation here: https://docs.snapcraft.io/snap-documentation/3781
 
-This is the core of the snap. You'll want to start here when it comes to adding code. And you may not need to leave this file at all.
+There are several important files and directories in MicroStack, some
+of which are like those in other snaps, some of which are unique to
+MicroStack:
 
-### `./snap-overlay`
+### The Snapcraft yaml
 
-Any files you add to snap-overlay will get written to the corresponding place in the file hierarchy under `/snap/microstack/common/`. Drop files in here if you want to insert a file or directory that does not come bundled by default with the Openstack source tarballs.
+    ./snapcraft.yaml
 
-### `./snap-overlay/snap-openstack.yaml`
+This is the core of the snap. You'll want to start here when it comes
+to adding code. And you may not need to leave this file at all.
 
-This is a yaml file unique to Snaps created by the Openstack team at Canonical. It creates a command called `snap-openstack`, which wraps Openstack daemons and scripts.
+### Snap overlay
 
-Documentation for this helper lives here: https://github.com/openstack/snap.openstack
+    ./snap-overlay
+
+Any files you add to snap-overlay will get written to the
+corresponding place in the file hierarchy under
+`/snap/microstack/common/`. Drop files in here if you want to insert a
+file or directory that does not come bundled by default with the
+OpenStack source tarballs.
+
+### Snap-openstack yaml
+
+    ./snap-overlay/snap-openstack.yaml
+
+This is a yaml file unique to Snaps created by the OpenStack team at
+Canonical. It creates a command called `snap-openstack`, which wraps
+OpenStack daemons and scripts.
+
+Documentation for this helper lives here:
+https://github.com/openstack/snap.openstack
 
 It's installed by the openstack-projects part.
 
-If you're adding an Openstack component to the snap, you may find it useful to take a look at the parts and apps that take advantage of snap-openstack, and add your own section to `snap-openstack.yaml`.
+If you're adding an OpenStack component to the snap, you may find it
+useful to take a look at the parts and apps that take advantage of
+snap-openstack, and add your own section to `snap-openstack.yaml`.
 
-### Filing Bug and Submitting Pull Requests
+### Filing bugs and submitting pull requests
 
-We track bugs and features on launchpad, at https://bugs.launchpad.net/microstack
+We track bugs and features on Launchpad, at
+https://bugs.launchpad.net/microstack
 
-To submit a bugfix or feature, please fork the github repo, and create a pull request against it. The microstackers team will see it and review your code.
+To submit a bugfix or feature, please create a Merge Proposal against
+the OpenDev repository. See the OpenStack Developer's Guide for more
+detail: https://docs.openstack.org/infra/manual/developers.html