Added qmake config examples for release and ccache builds

Building-from-source.md

@@ -1,12 +1,34 @@
-If you cannot use docker, you can build the sources in your own environment. Please make sure that you use the latest & greatest tools available (Qt-version, qmake, lrelease, compiler, etc.).
+Please make sure that you use the latest & greatest tools available (Qt-version, qmake, lrelease, compiler, etc.).
 
-Currently this is the only way to get certain extra functionality working (Bugs [#59](https://github.com/0xFEEDC0DE64/QtZeiterfassung/issues/59), [#60](https://github.com/0xFEEDC0DE64/QtZeiterfassung/issues/60), [#61](https://github.com/0xFEEDC0DE64/QtZeiterfassung/issues/61))
+1. Get the sources & create build folder
+    ```
+    git clone --recursive https://github.com/0xFEEDC0DE64/QtZeiterfassung.git
+    mkdir build_QtZeiterfassung
+    cd build_QtZeiterfassung
+    ```
 
-```
-git clone --recursive https://github.com/0xFEEDC0DE64/QtZeiterfassung.git
-mkdir build_QtZeiterfassung
-cd build_QtZeiterfassung
-qmake ../QtZeiterfassung
-make
-make install # only needed on first build to copy needed resources
-```
+2. Create Makefiles using qmake (run only one of the following, depending on your needs)
+    ```
+    #debug build
+    qmake ../QtZeiterfassung
+
+    #release build
+    qmake ../QtZeiterfassung -config release
+
+    #debug build with ccache
+    qmake CONFIG+=ccache ../QtZeiterfassung
+
+    #release build with ccache
+    qmake CONFIG+=ccache ../QtZeiterfassung -config release
+    ```
+
+3. Compile
+    ```
+    make -j8
+    make install # only needed on first build to copy needed resources
+    ```
+
+4. Run the tool
+    ```
+    ./bin/zeiterfassung.sh
+    ```