update docs (#498)

README.md

@@ -15,8 +15,6 @@ Poor man's function as a service.
 - [Introduction](#introduction)
 - [Installation](#installation)
 - [Usage](#usage)
-- [Contribute](#contribute)
-
 
 ## Introduction
 
@@ -77,9 +75,6 @@ NAME:
 USAGE:
    fx [global options] command [command options] [arguments...]
 
-VERSION:
-   0.9.33
-
 COMMANDS:
    up        deploy a function
    down      destroy a service
@@ -110,7 +105,7 @@ $ fx up --name hello ./examples/functions/JavaScript/func.js
 
 #### Remote host
 
-Use `--host` to specify the target host for your function,
+Use `--host` to specify the target host for your function, or you can just set it to `FX_HOST` environment variable.
 
 ```shell
 $ fx up --host roo@<your host> --name hello ./examples/functions/JavaScript/func.js
@@ -220,31 +215,6 @@ $ FX_KUBECONF=~/.kube/config fx up examples/functions/JavaScript/func.js --name
 fx infra create --type k3s --name fx-cluster-1 --master root@123.11.2.3 --agents 'root@1.1.1.1,root@2.2.2.2'
 ```
 
-## Contribute
-
-fx uses [Project](https://github.com/metrue/fx/projects/4) to manage the development.
-
-#### Prerequisites
-
-Docker: make sure [Docker](https://docs.docker.com/engine/installation/) installed and running on your server.
-
-
-<a name="buildtest"></a>
-#### Build & Test
-
-```
-$ git clone https://github.com/metrue/fx
-$ cd fx
-$ make build
-```
-
-Then you can build and test:
-
-```
-$ make build
-$ ./build/fx -h
-```
-
 
 ## Contributors
 

bundler/README.md

@@ -0,0 +1,63 @@
+The only thing `fx` does is to make a single function to be an HTTP service, `fx` takes two steps to finish the process,
+* Wraps the function into a web server project and make it be the handler function of the HTTP request.
+* Builds the bundled web server to be Docker image, then run it as a Docker container and expose the service port.
+
+`bundler` is the component responsible for step 1: wrap a single function (and its dependencies) into a web server.  Take a Node web service as an example, the project looks like this,
+```
+helloworld
+├── Dockerfile
+├── app.js
+└── fx.js
+```
+
+And the codes is pretty simple,
+
+**app.js**
+```javascript
+const Koa = require('koa');
+const bodyParser = require('koa-bodyparser');
+const cors = require('@koa/cors');
+const fx = require('./fx');
+
+const app = new Koa();
+app.use(cors({
+  origin: '*',
+}));
+app.use(bodyParser());
+app.use(fx);
+
+app.listen(3000);
+```
+
+**fx.js**
+```javascript
+module.exports = (ctx) => {
+  ctx.body = 'hello world'
+}
+```
+
+**Dockerfile**
+```dockerfile
+FROM metrue/fx-node-base
+
+COPY . .
+EXPOSE 3000
+CMD ["node", "app.js"]
+```
+
+You can see that it's a web service built with `Koa`,  the request handler function defined in `fx.js` to response plain text `hello world`,  so to make a general JavaScript/Node function to be a web service, we only have to put it into `fx.js` above, then build and run it with Docker and that's it.
+
+To support different programming languages, `fx` needs to implement different `bundlers`, the reasons are,
+* The way to set up a web service is different in different languages
+* The way to manage dependency is different in different languages.
+
+So there will be (are) different `bundlers` in `fx`.
+```
+go-bundler: based on Gin
+ruby-bundler: based on Sinatra
+node-bundler: based on Koa
+python-bundler: based on flask
+...
+```
+
+