Improve README

- Add instructions to build package
- Add instructions to contribute

README.md

@@ -8,3 +8,47 @@ Unofficial .deb Packages of the Eclipse IDE for Java Developers for Ubuntu
 ``sudo apt-get update``
 
 ``sudo apt-get install eclipse-ide-java``
+
+## Contributing
+
+### Install Debian developer tools
+
+```
+$ sudo apt-get install devscripts build-essential lintian
+```
+
+## Rename package directory
+
+```
+mv eclipse-ide-java-* <new eclipse version>
+cd <new eclipse version>
+```
+
+All the magic happens in this directory.
+
+## Rename orig package
+
+```
+mv eclipse-ide-java_*orig.tar.gz eclipse-ide-java_<new version>.orig.tar.gz
+```
+
+### Modify changelog
+
+Modify `debian/changelog` file, inserting your name and modification **on top**
+of the file.
+
+## Modify preinst
+
+Modify `debian/preinst` with the correct URL to download Eclipse for.
+
+## Build your package
+
+`$ debuild -us -uc`
+
+## Test your package
+
+`$ sudo dpkg -i ../eclipse-ide-java_<new eclipse version>-1_amd64.deb`
+
+## Push your changes
+
+Open a branch, send us your modifications and wait for merging.