rpmbuild: add motd msg for the builder

rpmbuild/copr-rpmbuild.spec

@@ -251,6 +251,9 @@ install -p -m 755 bin/copr-sources-custom %buildroot%_bindir
 install -p -m 755 bin/copr-rpmbuild-cancel %buildroot%_bindir
 install -p -m 755 bin/copr-rpmbuild-log %buildroot%_bindir
 install -p -m 755 bin/copr-rpmbuild-loggify %buildroot%_bindir
+mkdir -p %{buildroot}%{_sysconfdir}/copr-builder
+install -p -m 644 etc/copr-builder/hello-msg.txt \
+    %{buildroot}%{_sysconfdir}/copr-builder
 
 name="%{name}" version="%{version}" summary="%{summary}" %py_install
 
@@ -308,6 +311,7 @@ install -p -m 644 copr_distgit_client.py %{buildroot}%{expand:%%%{python}_siteli
 %_sysconfdir/copr-builder
 %dir %mock_config_overrides
 %doc %mock_config_overrides/README
+%config %_sysconfdir/copr-builder/hello-msg.txt
 
 
 %files -n copr-distgit-client

rpmbuild/etc/copr-builder/hello-msg.txt

@@ -0,0 +1,37 @@
+You have been entrusted with access to a Copr builder.
+Please be responsible.
+
+This is a private computer system, unauthorized access is strictly
+prohibited. It is to be used only for Copr-related purposes,
+not as your personal computing system.
+
+Please be aware that the legal restrictions for what you can build
+in Copr apply here as well.
+https://docs.pagure.org/copr.copr/user_documentation.html#what-i-can-build-in-copr
+
+You can display more help on how to use the builder by running copr-builder:
+    $ copr-builder --help
+
+What to do next?
+By default, the builder will be destroyed after 30 minutes. Extend
+this period with:
+    $ copr-builder prolong
+
+The selected (in Copr web UI) build was automatically resubmitted,
+you can find the process with:
+    $ ps ax | grep '[c]opr-rpmbuild'
+
+You can reproduce Copr builds on your this machine by running copr-rpmbuild
+specified in the builder-live logs. For example:
+
+    $ /usr/bin/copr-rpmbuild --verbose --drop-resultdir --srpm --task-url {BUILD_TASK_URL}
+
+The results are produced in `/var/lib/copr-rpmbuild/`. See the
+information at the beginning of the builder-live.log on how to
+reproduce the build manually.
+
+Once you are finished and don't need the builder anymore,
+please return it using:
+    $ copr-builder release
+
+Happy debugging.