Add install to Cheatsheet/deb

cheat/cheatsheets/deb

@@ -1,3 +1,7 @@
 # Extract contents of a .deb file
 $ ar vx foo.deb    # -> data.tar.gz
 $ tar xf data.tar.gz
+
+# Install .deb file to a debian like system, e.g. ubuntu
+$ sudo dpkg -i foo.deb
+$ sudo apt-get install -f