Add installing instructions

README.md

@@ -29,6 +29,7 @@ Some of these formulas are from the excellent book by Jean Meeus "Astronomical A
 ## Libraries
 
 GTK is used to create the GUI.
+GDK and Cairo is used for the plots.
 Libhandy is used to fit on small screens.
 Curl (and Json) is used to connect to "Nominatim" (OpenStreetMap) to translate searched words into coordinates.
 
@@ -37,6 +38,13 @@ Curl (and Json) is used to connect to "Nominatim" (OpenStreetMap) to translate s
 At the moment this application is NOT functional and I only test this application with Gnome Builder.
 Some parts of Libhandy like "HdyViewSwitcherBar" are only showen correctly with "Adwaita" as theme.
 
+```diff
+meson builddir
+cd builddir
+ninja
+ninja install
+``
+
 ## Screenshots
 
 <a href='https://gitlab.com/Zwerg12/picplanner/-/blob/master/screenshots/screenshot-large.png'><img height='300px' alt='screenshot-large' src='https://gitlab.com/Zwerg12/picplanner/-/raw/master/screenshots/screenshot-large.png'/></a>