[enh] contribution guide added

Contribution-Guide.md

@@ -0,0 +1,58 @@
+## How to contribute
+
+### Prime directives: Privacy, Hackability
+
+Searx has 2 prime directives, privacy-by-design and hackability.
+The hackability comes in at least 3 levels:
+
+ - support for search engines
+ - plugins for altering search behaviour
+ - hacking searx itself.
+
+Happy hacking. Observe the lack of "world domination" among the directives,
+searx has no intentions for wide mass-adoption, rounded corners, etc. The prime
+directive: "privacy" - deserves a seperate chapter, as it's quite uncommon
+unfortunately, here it goes:
+
+#### Privacy-by-design
+
+Searx is a privacy-respecting, hackable meta-search engine. It was born out of
+the need for a privacy-respecing search facility that can be expanded easily to
+maximise both its search and it's privacy protecting capabilities.
+
+Consequences of Privacy-by-design are that some widely used features work
+differently or not by default or at all. If some feature reduces the privacy
+perserving aspects of searx, it should by default be switched of, if
+implemented at all. There is enough search engines already out there providing
+such features. =\ Since privacy-preservation is a prime goal, if some feature
+does reduce the protection of searx and is implemented, care should be taken to
+educate the user about the consequences of choosing to enable this. Further
+features which implement widely known features in a manner that protects
+privacy but thus deviate from the users expectations should also be explained
+to the user. Also if you think that something works weird with
+searx, maybe it's because of the tool you use is designed in a way to interfere
+with privacy respect, submiting a bugreport to the vendor of the tool that
+misbehaves might be a good feedback for the vendor to reconsider his disrespect
+towards his customers (e.g. GET vs POST requests in various browsers).
+
+Remember the other prime directive of searx is to be hackable, so if the above
+privacy concerns do not fancy you, simply fork it.
+
+### Code
+
+Code modifications are accepted in pull requests, don't forget to add yourself to the AUTHORS file.
+
+Python code follows all the pep8 standards except maximum line width which is 120 char.
+
+Please be sure that the submitted code doesn't break existing tests and follows coding conventions.
+
+If new functionality implemented, tests are highly appreciated.
+
+### Translation
+
+Translation currently happens on [transifex](https://transifex.com/projects/p/searx).
+Please do not update translation files in the repo.
+
+### Documentation
+
+The main place of the documentation is this wiki, updates are welcome.

Home.md

@@ -9,6 +9,7 @@
 
 ## developer documentation
 
+* [Contribution guide](https://github.com/asciimoo/searx/wiki/Contribution-Guide)
 * [Translation guide](https://github.com/asciimoo/searx/wiki/Translation)
 * [Plugins](https://github.com/asciimoo/searx/wiki/Plugins)
 * [Compiling Styles](https://github.com/asciimoo/searx/wiki/Styles)