include path parameters in params hash for ruby environment (#249)

* include path parameters in params hash for ruby environment

* Improve code organization and documentation for ruby environment.

* Document Ruby examples

examples/ruby/README.md

@@ -0,0 +1,107 @@
+# Ruby examples
+
+This directory contains several examples to get you started using Ruby
+with Fission.
+
+Before running any of these functions, make sure you have created a
+`ruby` Fission environment:
+
+```
+$ fission env create --name ruby --image USER/ruby-env
+```
+
+## Method signature
+
+A standard Ruby function has the basic form:
+
+```ruby
+def handler(context)
+  return [200, {}, []]
+end
+```
+
+If the fission context is not required, the function can be simplified:
+
+```ruby
+def handler
+  [200, {}, ["Hello, world!\n"]]
+end
+```
+
+If a simple text response is to be returned, with a status of 200, this
+can be further simplified.
+
+```ruby
+def handler
+  "Hello, world!\n"
+end
+```
+
+## Hello example (`hello.rb`)
+
+This example is the simplest possible Ruby function, as described above.
+
+To run the example:
+
+```
+$ fission function create --name hello --env ruby --code examples/ruby/hello.rb
+
+$ fission route create --method GET --url /hello --function hello
+
+$ curl http://$FISSION_ROUTER/hello
+  Hello, world!
+```
+
+## Request data example (`request_data.rb`)
+
+This example shows basic use of the `Fission::Context` and
+`Fission::Request` objects.
+
+To run the example:
+
+```
+$ fission function create --name request --env ruby --code examples/ruby/request_data.rb
+
+$ fission route create --method GET --url /request/{id} --function request
+
+$ curl http://$FISSION_ROUTER/request/123?key=abc
+  ---ENV---
+  GATEWAY_INTERFACE=CGI/1.1
+  PATH_INFO=/
+  QUERY_STRING=key=abc
+  REMOTE_ADDR=172.17.0.8
+  REMOTE_HOST=172.17.0.8
+  REQUEST_METHOD=GET
+  REQUEST_URI=http://192.168.64.200:31314/?key=abc
+  SCRIPT_NAME=
+  SERVER_NAME=192.168.64.200
+  SERVER_PORT=31314
+  SERVER_PROTOCOL=HTTP/1.1
+  SERVER_SOFTWARE=WEBrick/1.3.1 (Ruby/2.4.1/2017-03-22)
+  HTTP_HOST=192.168.64.200:31314
+  HTTP_USER_AGENT=curl/7.52.1
+  HTTP_ACCEPT=*/*
+  HTTP_X_FISSION_PARAMS_ID=123
+  HTTP_X_FORWARDED_FOR=172.17.0.1
+  HTTP_ACCEPT_ENCODING=gzip
+  rack.version=1=3
+  ...
+  HTTP_VERSION=HTTP/1.1
+  REQUEST_PATH=/
+
+  ---HEADERS---
+  Accept: */*
+  Accept-Encoding: gzip
+  Host: 192.168.64.200:31314
+  User-Agent: curl/7.52.1
+  Version: HTTP/1.1
+  X-Fission-Params-Id: 123
+  X-Forwarded-For: 172.17.0.1
+
+  ---PARAMS---
+  key=abc
+  id=123
+
+  --BODY--
+
+```