Update README

Use markdown formatting (which displays more nicely in GitLab now that
we migrated) and give a bit of context to users.

Makefile.am

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 	valgrind-suppressions
 
 EXTRA_DIST = \
+	README.md \
 	COPYING.TESTS \
 	meson_options.txt \
 	meson.build \

README

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-GObject based library for accessing the Secret Service API.
-

README.md

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+libsecret
+=========
+
+A [GObject]-based library for accessing the Secret Service API of the
+[freedesktop.org project], a cross-desktop effort to access passwords, tokens
+and other types of secrets. libsecret provides a convenient wrapper for these
+methods so consumers do not have to call the low-level DBus methods.
+
+The actual Secret Service API spec can be found at
+https://specifications.freedesktop.org/secret-service/.
+
+Building
+--------
+
+To build and install libsecret, you can use the following commands:
+
+```
+$ meson _build
+$ ninja -C _build
+$ ninja -C _build install
+```
+
+Contributing
+-------------
+
+You can browse the code, issues and more at libsecret's [GitLab repository].
+
+If you find a bug in libsecret, please file an issue on the [issue tracker].
+Please try to add reproducible steps and the relevant version of libsecret.
+
+If you want to contribute functionality or bug fixes, please open a Merge
+Request (MR). For more info on how to do this, see GitLab's [help pages on
+MR's].
+
+If libsecret is not translated in your language or you believe that the
+current translation has errors, you can join one of the various translation
+teams in GNOME. Translators do not commit directly to Git, but are advised to
+use our separate translation infrastructure instead. More info can be found at
+the [translation project wiki page].
+
+
+
+[GObject]: https://developer.gnome.org/gobject/stable/
+[freedesktop.org project]: https://www.freedesktop.org/
+[GitLab repository]: https://gitlab.gnome.org/GNOME/libsecret
+[help pages on MR's]: https://docs.gitlab.com/ee/gitlab-basics/add-merge-request.html
+[issue tracker]: https://gitlab.gnome.org/GNOME/libsecret/issues
+[translation project wiki page]: https://wiki.gnome.org/TranslationProject/