Document local package builds

Readme.md

@@ -10,7 +10,7 @@ an application for performing [Monte Carlo] simulations of ion implantation.
 * The code is maintained by the Low Energy Muons ([LEM]) group at the Paul Scherrer Institute ([PSI]). 
 * The [GUI] is written in [Node.js], [JavaScript] and [Electron]. 
 * The binary (statically linked) from the [Fortran] code is also included.
-* [RPM] and [DEB] packages are also included.
+* Linux packages can be generated locally from the current source tree.
 
 Further information can be found in the following publications:
 
@@ -39,7 +39,8 @@ Further information can be found in the following publications:
 
 ### Installation ###
 
-For a simple installation you may use the included RPM or Debian packages which come with statically linked binaries. See instructions below if you prefer a manual installation. 
+Packages are not stored in this repository. You can either run the application
+directly from source or build Linux packages locally as described below.
 
 ###### Fortran code compilation ######
 
@@ -68,6 +69,35 @@ npm start
 Note: you do not need to run `npm install` every time.
 Next time you can simply run `npm start` only. 
 
+###### Building RPM and DEB packages ######
+
+Install [Node.js] (`nodejs`, `nodejs-libs` and `npm`), then run:
+
+```bash
+cd trimsp
+npm install
+npm run make
+```
+
+This uses Electron Forge to build Linux packages from the current checkout.
+
+The generated files are written under:
+
+```text
+out/make/deb/x64/
+out/make/rpm/x64/
+```
+
+Typical output files are:
+
+```text
+out/make/deb/x64/trimsp_<version>_amd64.deb
+out/make/rpm/x64/TrimSP-<version>-1.x86_64.rpm
+```
+
+Depending on the host system, additional packaging tools may be required for
+the RPM/DEB build chain.
+
 ###### Deploying on a web server ######
 
 The browser version requires a server-side setup in addition to the static