docs(dev.md): keep some info about structure

README.md

@@ -50,6 +50,7 @@ We appreciate any contribution to Mobilizon. Check [our contributing page](https
   * 🔢 Pick an instance [https://mobilizon.org](https://mobilizon.org)
   * 💻 Source: [https://framagit.org/framasoft/mobilizon](https://framagit.org/framasoft/mobilizon)
   * 📜 Documentation [https://docs.joinmobilizon.org](https://docs.joinmobilizon.org)
+    * A summarized description of structure of sources is done in [`docs/dev.md`](./docs/dev.md)
   
 ### Discuss
   * 💬 Element/Matrix: [https://matrix.to/#/#Mobilizon:matrix.org](https://matrix.to/#/#Mobilizon:matrix.org)

docs/dev.md

@@ -0,0 +1,30 @@
+# Documentation for developpers
+
+_This file is a summary of the documentation for developpers. As explained in [CONTRIBUTING.md](../CONTRIBUTING.md), the main documentation is available at <https://docs.joinmobilizon.org/contribute/>_
+
+## Technologies
+
+Mobilizon is an app that uses:
+  * [Elixir](https://elixir-lang.org/) for backend,
+  * [VueJS](https://vuejs.org/) for front-end
+  * [GraphQL](https://graphql.org/) as it's API layer
+
+[GraphQL](https://graphql.org/) is managed using:
+  * [Absinthe](https://absinthe-graphql.org/) on the backend
+  * [VueApollo](https://apollo.vuejs.org/) on the front-end.
+  
+[UI](https://en.wikipedia.org/wiki/User_interface) is handled with [Tailwind](https://tailwindcss.com/) and [Oruga](https://oruga.io/).
+
+## Structure of sources
+
+  * `config` backend compile-time and runtime configuration
+  * `docker` 🐳
+  * `js/src` Front-end
+  * `lib/federation` Handling all the federation stuff (sending and receving activities, converting activities, signatures, helpers…)
+  * `lib/graphql/schema` The schema declarations for the GraphQL API
+  * `lib/graphql/resolvers` The logic behind the GraphQL API
+  * `lib/mix/tasks` CLI
+  * `lib/mobilizon` model structures, database queries
+  * `lib/service` various services
+  * `lib/web` controllers, middlewares, auth-related stuff
+  * `test` tests