Update docs a little bit

INSTALL.md

@@ -28,7 +28,8 @@ folder. To build it, enter the folder and run the commands described above.
 	- network
 - A pdf rendering backend (optional, see below)
 - qrencode (optional)
-- (lib)unarr (see below)
+- 7zip or p7zip (see below)
+- (lib)unarr (optional, see below)
 
 Not all dependencies are needed at build time. For example the qml components in
 YACReaderLibrary (GridView, InfoView) will only show a white page if the
@@ -39,7 +40,16 @@ This can also happen if these dependencies are too old (i.e Qt < 5.6 is used).
 
 ### Decompression
 
-YACReader uses [(lib)unarr](https://github.com/selmf/unarr) for comic book archive
+Configure the library you want to use throught `qmake` `CONFIG`. `CONFIG += 7zip` or `CONFIG += unarr`, if not specified `7zip` is used in MacOS and Windows and `unarr` in Linux.
+
+#### 7zip
+
+YACReader uses by default [7zip](https://www.7-zip.org/) for comic book archive
+decompression. In MacOS and Linux, it uses [p7zip](http://p7zip.sourceforge.net/). Please read `compressed_archive/README_7zip.txt` for more details. This is the recomended library since supports a wider variety of formats, including RAR5 and 7z.
+
+#### unarr
+
+YACReader can use [(lib)unarr](https://github.com/selmf/unarr) for comic book archive
 decompression. Most Linux distributions don't ship this library yet, so you will
 probably have to build it yourself.
 

README.md

@@ -23,7 +23,6 @@ This software has been developed by Luis Ángel San Martín Rodríguez
 See [INSTALL.md](./INSTALL.md)
 
 ## Contact
-
 - Project home page : www.yacreader.com
 - e-mail:
    - info@yacreader.com
@@ -37,7 +36,18 @@ See [INSTALL.md](./INSTALL.md)
 If you need help or have any suggestion, please, send me an e-mail.
 
 ## Contributing
+If you are interested in contributing to the project the first step should be to contact me so we can plan together the best approach, you can send an e-mail or just open an issue in this repo. For small bug fixes it is usually ok to open a PR directly. 
+
+Contributions are not restricted to code, you can help the project by bringning new UI/UX ideas, designing new assets, writting manuals or tutorials, translating the apps, etc. If you are interested in DevOps, YACReader uses Azure Pipelines for CI/CD, any improvements in that area are welcome. Testing preleases is also really appreciated.
+
+#### Code
+YACReader uses `clang-format` to ensure a common style and avoid deviances from it. CI checks this and will fail if the correct format is not used. `clang-format` needs to be called recusivelly in all the folders because some of them have the own `.clang-format` file, mainly to exclude changing the format in thirdparty libraries which are included in the source code. I recommend to configure your development tools to use `clang-format`, you can try to use it manually, but please, do it always before commiting changes. I recommend using QtCreator configured properly, you can find a tutorial [here]( https://www.vikingsoftware.com/using-clang-format-with-qtcreator/).
+
+#### CI/CD
+Any PR will be validated through CI, and it will not be merged if CI fails.
+
+#### Pull Requests
+The base and target branch for any PR should always be `develop`.
 
 ## Donations
-YACReader is free but it needs money to still be alive, so please,
+YACReader is free but it needs money to still be alive, so please, if you like YACReader, visit the home page and make a donation.
-if you like YACReader, visit the home page and make a donation.