Add FluxDown to Downloader & Manager (#704)

Co-authored-by: zerx-lab <zerx-lab@users.noreply.github.com>

README.md

@@ -313,6 +313,7 @@ A list of **Free** and **Open Source Software** ***(FOSS)*** for **Android** –
 * [**Aria2App**](https://github.com/devgianlu/Aria2App) <sup>**[[F-Droid](https://f-droid.org/packages/com.gianlu.aria2app)]**</sup>
 * [**Download Navi**](https://github.com/TachibanaGeneralLaboratories/download-navi) <sup>**[[F-Droid](https://f-droid.org/packages/com.tachibana.downloader)]**</sup>
 * [**dvd**](https://github.com/yausername/dvd) <sup>**[[F-Droid](https://f-droid.org/packages/org.yausername.dvd)]**</sup>
+* [**FluxDown**](https://github.com/zerx-lab/FluxDown)
 * [**Gopeed**](https://github.com/GopeedLab/gopeed)
 * [**LibreTorrent**](https://github.com/proninyaroslav/libretorrent) <sup>**[[F-Droid](https://f-droid.org/packages/org.proninyaroslav.libretorrent)]**</sup>
 * [**Myne**](https://github.com/Pool-Of-Tears/Myne) <sup>**[[F-Droid](https://f-droid.org/packages/com.starry.myne)]**</sup> <sup>**[[IzzyOnDroid](https://apt.izzysoft.de/packages/com.starry.myne)]**</sup>
@@ -1004,6 +1005,7 @@ A list of **Free** and **Open Source Software** ***(FOSS)*** for **Android** –
 
 ### • Educational
 
+* [**Braincup**](https://github.com/SimonSchubert/Braincup) <sup>**[[F-Droid](https://f-droid.org/packages/com.inspiredandroid.braincup)]**</sup>
 * [**Digits**](https://github.com/foxtrotdev/learn-digits) <sup>**[[F-Droid](https://f-droid.org/packages/eu.mokrzycki.learndigits)]**</sup>
 * [**Everest**](https://github.com/mwageringel/everest) <sup>**[[F-Droid](https://f-droid.org/packages/io.github.mwageringel.everest)]**</sup>
 * [**GCompris**](https://invent.kde.org/education/gcompris.git) <sup>**[[F-Droid](https://f-droid.org/packages/net.gcompris.full)]**</sup>