Add build/test/release instructions. (opentracing#28)

Author: carlosalberto

README.md

@@ -4,9 +4,28 @@
 
 A python version of the "BasicTracer" reference implementation for OpenTracing.
 
-## Build, install and run tests
+## Development
 
+### Tests
+
+```sh
+virtualenv env
+. ./env/bin/activate
+make bootstrap
+make test
 ```
-make bootstrap; make test
+
+### Releases
+
+Before new release, add a summary of changes since last version to CHANGELOG.rst
+
+```sh
+pip install zest.releaser[recommended]
+prerelease
+release
+git push origin master --follow-tags
+python setup.py sdist upload -r pypi
+postrelease
+git push
 ```