Merge pull request #232 from tendermint/contributing

Add contribution guidelines

CONTRIBUTING.md

@@ -0,0 +1,63 @@
+# Contributing
+
+Thank you for considering making contributions to go-amino! This repository follows the [contribution guidelines] of 
+tendermint and the corresponding [coding repo]. Please take a look if you are not already familiar with those.
+
+Besides what you can find in aforementioned resources, there are a few things to consider specific to go-amino. 
+They are outlined below.
+
+## Compatibility
+
+### Protobuf
+
+Amino aims to be and stay [protobuf] compatible. Please, ensure that any change you add retains protobuf compatibility.
+Basic compatibility is ensured by tests. To not introduce a protobuf dependency, these tests are not run with every test 
+run, though. You need to turn on a [build flag] to build and run those tests.
+
+### Tendermint
+
+Please ensure that tendermint still passes all tests when run with your changes. You can do so by cloning [tendermint].
+Then update the dependency to your commit (or release) in the corresponding [Gopkg.toml] and run `dep ensure -v` to get 
+tendermint build with your amino version. Finally, run `make test` (all in the tendermint project directory).
+
+
+## Fuzzers
+
+Amino is fuzzed using several fuzzers. At least run [gofuzz] by running the command:
+```
+make test
+```
+This is what circle-ci will also run for you.
+
+Ideally, run the more in-depth [go-fuzzer], too. They are currently not run by circel-ci and we need to run it manually 
+for any substantial change.
+If go-fuzzer isn't installed on your system, make sure to run:
+```
+go get -u github.com/dvyukov/go-fuzz/go-fuzz-build github.com/dvyukov/go-fuzz/go-fuzz
+```
+
+The fuzzers are run by:
+```
+make gofuzz_json
+```
+and
+```
+make gofuzz_binary
+```
+respectively. Both fuzzers will run in an endless loop and you have to quit them manually. They will output 
+any problems (crashers) on the commandline. You'll find details of those crashers in the project directories 
+`tests/fuzz/binary/crashers` and `tests/fuzz/json/crashers` respectively. 
+
+If you find a crasher related to your changes please fix it, or file an issue containing the crasher information.
+
+
+[contribution guidelines]: https://github.com/tendermint/tendermint/blob/master/CONTRIBUTING.md
+[coding repo]: https://github.com/tendermint/coding
+[gofuzz]: https://github.com/google/gofuzz
+[go-fuzzer]: https://github.com/dvyukov/go-fuzz
+[protobuf]: https://developers.google.com/protocol-buffers/
+[build flag]: https://github.com/tendermint/go-amino/blob/faa6e731944e2b7b6a46ad202902851e8ce85bee/tests/proto3/proto3_compat_test.go#L1
+[tendermint]: https://github.com/tendermint/tendermint/
+[Gopkg.toml]: https://github.com/tendermint/tendermint/blob/master/Gopkg.toml
+
+