android: add F-Droid metadata file and fdroidserver package to guix environment

.fdroid.yml

@@ -0,0 +1,28 @@
+Categories:
+  - Internet
+License: GPL-3.0-or-later
+WebSite: https://forge.monarch-pass.net/malacoda/piecannon
+SourceCode: https://forge.monarch-pass.net/malacoda/piecannon
+IssueTracker: https://forge.monarch-pass.net/malacoda/piecannon/issues
+
+Name: PieCannon
+Summary: File sharing tool
+Description: Tool for sharing files through the web.
+
+RepoType: git
+Repo:  https://forge.monarch-pass.net/malacoda/piecannon
+
+Builds:
+  - versionName: "1.0"
+    versionCode: 1
+    commit: HEAD
+    build:
+        - mvn clean install -f ../lib/pom.xml
+        - mvn clean install
+    subdir: android
+    output: target/*.apk
+
+AutoUpdateMode: None
+UpdateCheckMode: RepoManifest
+CurrentVersion: "1.0"
+CurrentVersionCode: 1

README.md

@@ -10,6 +10,11 @@ Run `mvn clean install` in this directory to build the `lib` and `desktop` modul
 
 If the `ANDROID_HOME` environment variable exists, `android` will also be built.
 
+Under GNU Guix System, the `guix_activate_environment` script can be used to create an environment that contains necessary packages for building this app.
+
+### F-Droid
+If the `fdroid` command is available, the app can be built using `fdroid build`. The Guix environment script will add the `fdroidserver` package to the generated environment.
+
 ## How to install
 ### GNU/Linux
 `desktop` contains a wrapper script that will call the version of `piecannon-desktop-app` installed in your maven repository, and then open the uploaded file in your browser. You can copy or symlink this wrapper script anywhere. Typically you would put it in `~/bin` or `~/.local/bin`. Make sure that directory is in your `PATH`.

guix_activate_environment

@@ -1,2 +1,2 @@
 #!/bin/sh
-guix environment --ad-hoc icedtea:jdk maven
+guix environment --ad-hoc icedtea:jdk maven fdroidserver