[gnome-keysign/flatpak] flatpak: Updated README to show modern ways to install the app

[Tobias Mueller <tobiasmue src gnome org>]

commit 3d10775323631db85a76503224a7fcd81c5dfca9
Author: Tobias Mueller <muelli cryptobitch de>
Date:   Thu Feb 8 13:51:51 2018 +0100

    flatpak: Updated README to show modern ways to install the app

 flatpak/README.rst | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)
---
diff --git a/flatpak/README.rst b/flatpak/README.rst
index 06fad62..29763e1 100644
--- a/flatpak/README.rst
+++ b/flatpak/README.rst
@@ -30,14 +30,26 @@ To create a bundle file, use something like the following:
 Installation
 --------------
 
-Before you can install an application, you need to install a runtime.
-For now, we use the GNOME 3.20 runtime.
-If you haven't installed it yet, you can get it by running the following commands:
-
-    wget https://sdk.gnome.org/keys/gnome-sdk.gpg
-    flatpak --user remote-add --gpg-import=gnome-sdk.gpg gnome https://sdk.gnome.org/repo/
-    flatpak --user remote-add --gpg-import=gnome-sdk.gpg gnome-apps https://sdk.gnome.org/repo-apps/
-    flatpak --user install gnome org.gnome.Platform 3.20
+Several options for installing a flatpaked application exist.
+
+With a flatpakref you can have an application as well as its runtime
+installed with little effort.
+
+    flatpak install --from https://muelli.cryptobitch.de/tmp/2017-01-29-keysign.flatpakref
+
+
+If that does not work or you would like to install the application manually,
+e.g. because you want to install a particular version,
+you need to install a runtime first.
+We use a GNOME runtime which you can get from Flathub.
+In order to add flathub to your repositories, you can execute the following:
+
+    flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
+
+Then you can try to install the runtime with the following command:
+
+    flatpak --user install --runtime flathub org.gnome.Platform//3.26
+
 
 
 Then, if you have a bundle file of GNOME Keysign, you can do