Add support for opening UBZ files on Linux

release_scripts/linux/debian_package_files/postinst

@@ -15,5 +15,9 @@
 # ---------------------------------------------------------------------
 
 xdg-desktop-menu install --novendor /usr/share/applications/openboard.desktop
+xdg-mime install /opt/openboard/etc/openboard-ubz.xml
+xdg-mime default /usr/share/applications/openboard.desktop application/ubz
+
 ln -s /opt/openboard/run.sh /usr/bin/openboard
+
 exit 0

release_scripts/linux/package.sh

@@ -297,6 +297,7 @@ echo "Icon=/$APPLICATION_PATH/$APPLICATION_CODE/${APPLICATION_NAME}.png" >> $APP
 echo "StartupNotify=true" >> $APPLICATION_SHORTCUT
 echo "Terminal=false" >> $APPLICATION_SHORTCUT
 echo "Type=Application" >> $APPLICATION_SHORTCUT
+echo "MimeType=application/ubz"
 echo "Categories=Education;" >> $APPLICATION_SHORTCUT
 cp "resources/images/${APPLICATION_NAME}.png" "$PACKAGE_DIRECTORY/${APPLICATION_NAME}.png"
 

resources/linux/openboard-ubz.xml

+<?xml version="1.0"?>
+<mime-info xmlns='http://www.freedesktop.org/standards/shared-mime-info'>
+  <mime-type type="application/ubz">
+    <comment>OpenBoard document file</comment>
+    <comment xml:lang="fr">Document OpenBoard</comment>
+    <glob pattern="*.ubz"/>
+  </mime-type>
+</mime-info>