add doc/DEVELOP.md instead of doc/README.md

doc/DEVELOP.md

@@ -0,0 +1,70 @@
+
+
+## Build mscp as deb package
+
+`make build-deb` produces a mscp deb package and related files. This
+target builds mscp with `debuild` inside a docker container
+(Dockerfile is `docker/build-deb.Docerfile`).
+
+
+```console
+mkdir build && cd build && cmake ..
+make build-deb
+```
+
+After that:
+
+```console
+$ ls debbuild
+mscp_0.1.3_amd64.build	    mscp_0.1.3_amd64.deb  mscp-dbgsym_0.1.3_amd64.ddeb
+mscp_0.1.3_amd64.buildinfo  mscp_0.1.3.dsc
+mscp_0.1.3_amd64.changes    mscp_0.1.3.tar.xz
+```
+
+### To publush mscp in launchpad PPA:
+
+1. write changes in `debian/changelog` at main branch (the date command needed here is `date -R`)
+2. switch to `ppa-focal` or `ppa-jammy` branch
+3. reblase to the `main` branch and modify `debian/changes`:
+   * change `UNRELEASED` to the release name (`focal` or `jammy`).
+4. run `make build-deb` at the build directory and `cd debbuild`
+5. sign the files with `debsign -k [GPGKEYID] mscp_X.X.X~X_source.changes`
+5. upload the files with `dput ppa:upaa/mscp mscp_X.X.X~X_source.changes`
+
+
+## Build mscp as (source) rpm package
+
+`make build-srpm` produces a mscp src.rpm package. This target builts
+mscp with `rpmbuild` inside a docker container (Dockerfile is
+`docker/build-srpm.Dockerfile`, generated from
+`build-srpm.Dockerfile.in` by cmake).
+
+```console
+mkdir build && cd build && cmake ..
+make build-srpm
+```
+
+After that:
+
+```console
+$ ls *.rpm
+mscp-0.1.3-1.el9.src.rpm
+```
+
+### To publish mscp in COPR:
+
+1. download `mscp-X.X.X-1.yyy.src.rpm`
+2. upload the src.rpm to Build page at COPR.
+
+
+
+## Update Document
+
+The docuemnt is `doc/mscp.rst` (at present). When `mscp.1.in` is
+modified, run `make update-rst` to make it up to date.
+
+```console
+mkdir build cd build && cmake ..
+make update-rst
+```
+