Add build instructions

README.md

@@ -1,3 +1,29 @@
 # SpaceExpansion
 
-Space conquest simulator
+Space conquest simulator
+
+## Build
+
+### Dependencies
+
+- SDL2
+- SDL2 Image
+- SDL2 TTF
+
+Install on Ubuntu or Debian :
+```sh
+apt install libsdl2-dev libsdl2-ttf-dev libsdl2-image-dev
+```
+
+### Make
+
+```sh
+cmake
+make
+```
+
+### Execute
+
+```sh
+./SpaceExpansion
+```