* gnu/services/cuirass.scm (<build-manifest>,
<simple-cuirass-configuration>): New records.
(build-manifest, build-manifest?, simple-cuirass-configuration,
simple-cuirass-configuration?, simple-cuirass-services): New procedures.
(%default-cuirass-config): New variable.
* gnu/tests/cuirass.scm (%cuirass-simple-test): New variable.
* doc/guix.texi (Continuous Integration): Document it.