[WIP] Contributing.md to be discussed on meeting.

CONTRIBUTING.md

 #+Title: Contributing
 
+## Humanities
+
+### Social contract
+
+1. Use and promote welcoming behavior to respect Code of Conduct
+
+2. We are Team as whole: here to help to each others
+  - knowing the unknown is a value but ignoring the unknown is a failure
+    - do not ask to ask: just ask
+    - there is no stupid question(s)
+    - there is no unique solution(s)
+
+3. Watch deadlines individually and collectively
+  - at 0% of the time of the task, agree on the /estimate of time to fix
+    the issue.
+  - at 50% of the estimated time of the task, push your last commit with ID of the issue.
+    - if the commit has [WIP] label: everything is fine as expected
+    - if the commit has [HELP] label: it warns members of the project some
+    - if the commit is not pushed, it warns the project manager something is going wrong
+  - at 100% of the time of the task, push your commit with ID of the
+    issue with the label [PR] for Pull Request and fill /spent time as
+    comment on the issue
+    - if the commit is not pushed, it warns all the team something is
+      going wrong.
+
+
+### Facing issues
+
+If you get stuck on a bug:
+* Set a timer for 1h
+* Make it reproducible
+  * Commit a version with the issue even if the code is work-in-progress [WIP].
+* Try to identify the root cause of the issue:
+  * Using the browser inspector
+  * Identify the code path
+* If it takes too long fill an issue and mark it as blocking.
+  Mention it on IRC and go to another task.
+
+
+
+## Coordination tools
+
+### IRC Interactions
+- OFTC #gargantext
+- contribute to the 2 weekly meetings
+- your nickname is personal and is used by the same person always
+
+### Code coordination
+
+Git is the main Concurrent Version system used by the project.
+[gitlab](https://gitlab.iscpif.fr) is used as development platform
+(others platforms are used for communication purpose mainly).
+
+#### Git branches
+
+Main branches are:
+* master/prod : stable version used by end users
+* testing     : candidate version for stable, tested by end users
+* dev         : unstable version for developers only
+
+##### Git Tips
+* fix the conflicts on your own branch before ask for [PR]
+* `git rebase dev`, make sure you do not diverge
+* do not add temporary files in your commits
+* `git add -p` : to review what you are about to commit
+
+#### Git Tips
+
 yarn first then psc-package are used to manage dependencies
 
 to build use ./build
@@ -8,5 +76,103 @@ to add a new dependency: psc-package install PACKAGE
 
 use git, commit and pull request :)
 
-## Indentation
-- 2 spaces
+
+
+
+# Source files organisation
+
+## Code Design
+- 2 spaces or more if needed by the compilator
+- line length < ? chars
+
+## Map of the source code
+
+TODO
+
+## Components/Specs
+
+* Small: one file in `Gargantext/Components/X.purs`
+* Medium/Big:
+
+```
+  Gargantext/Components/
+    X.purs
+    X/Types.purs
+    X/Specs.purs (only if big)
+```
+
+# Purescript
+
+## Minor style rules
+
+```
+f $ do --> f do
+
+f (do ...) --> f do
+
+if (expr == true) --> if expr
+```
+
+## Using the `Show` class
+
+* Always use generic deriving.
+* If we want a different output than the generic one it
+  means that we should use a different class than `Show`.
+
+## When to newtype?
+
+* When we need type class instances.
+* When the type is generic (`Int`, `String`).
+* In particular a `newtype` is not needed for records such as `State`.
+
+## Identation
+
+* HTML nodes:
+
+```
+  div []
+  [ div []
+    [ a [] [...]
+    , a [] [...]
+    ]
+  , div []
+    [ ...
+    , ...
+    ]
+  ]
+```
+
+* Record notation:
+
+```
+  { a: exp, b: exp }
+
+  { a: exp
+  , b: exp
+  }
+
+  { a :: Typ, b :: Typ }
+
+  { a :: Typ
+  , b :: Typ
+  }
+```
+
+# Routing (backend & frontend)
+
+## Backend
+
+Use `toUrl`
+Use `Config.REST` (`get`, `put`...)
+
+# Thermite usage
+
+## Minor style rules
+
+```
+cotransform --> modifyState
+
+void modifyState --> modifyState_
+
+performAction should be a local function
+```