Add CONTRIBUTING.md

CONTRIBUTING.md

@@ -0,0 +1,66 @@
+Contributing
+============
+
+Thank you for your interest!
+Issue and pull request are welcome!
+
+
+Development and Testing
+-----------------------
+We are weolcoming tha refactoring and implements operators.
+
+`rx` provides attractive code to users, like the general `std.range` and `std.algorithm`. But, its source code is unfortunately complicated.
+
+In particular, it is important a variety operators combination tests, and multithreading tests.
+
+### Things you will need
+
+* Linux, Mac OS X, or Windows
+* git (used for source version control).
+* Some D Compiler. dmd and ldc.
+* Latest dub (used for build and testing).
+* An IDE. We recommend [Visual Studio Code](https://code.visualstudio.com/download) with [code-d](https://marketplace.visualstudio.com/items?itemName=webfreak.code-d).
+* Use dfmt (with default settings) for code formatting.
+
+### Patterns
+Taking `map` as an example, the operator consists of the following three elements.
+
+- struct `MapObserver`
+- struct `MapObservable`
+- template function `map`
+
+#### MapObserver
+Observer's role is to provide concrete algorithms in the constructed pipeline.
+
+`MapObserver` has the function of passing processed values to Observer as source.
+
+#### MapObservable
+Observable as an operator has Observable as a source and has the role of processing a given Observer and constructing a pipeline.
+
+`MapObservable` has the function of wrapping the passed Observer in `MapObserver` and subscribing to Observable as source.
+
+Also, since Observable returns `Disposable`, it relays it.
+
+#### map
+It is utility function for build `MapObservable`.
+
+
+### Naming priority
+Unified naming conventions is important. It is now as follows.
+
+1. Look for similar operators from `std.algorithm`.
+2. If there are no similar operators, follow [Reactive X](http://reactivex.io/documentation/operators.html).
+
+
+Documentation
+-------------
+We are welcoming the tutorial documentation.
+
+For users, the goal is to think about the composition of the tutorial so that you can see how to use it, and to add practical examples.
+
+For developers, We think that the following things are necessary.
+
+- Manage the tutorial as part of the source.
+  - Since the contribution log remains, it is easy to understand later.
+  - Not separate it into another repository to avoid version inconsistency.
+- Keep docs as a simple API reference.

README.md

@@ -97,6 +97,11 @@ Supported compilers are `dmd` and `ldc` that latest 3 versions.
 This library is under the MIT License.  
 Some code is borrowed from [Rx.NET](https://github.com/Reactive-Extensions/Rx.NET).
 
+### Contributing
+Issue and PullRequest are welcome! :smiley:
+
+Refer to [CONTRIBUTING.md](/CONTRIBUTING.md) for details.
+
 ### Future work
 
 - generic observable factory