Update README

- Update tutorial
- Change architecture image
- Fix grammars

Signed-off-by: Yi-Soo An <yisooan@gmail.com>

README.md

@@ -1,9 +1,9 @@
 # Summary
-Currently, WebOS image build system is depended on Ubuntu. Linux users who usually use other distros, such as Fedora, Arch and so on could not build the image on their host for reasons, but one of them is the library dependencies. To provide the build system on any distros, dockerize it.
+Currently, webOS image build system is depended on Ubuntu. Linux users who usually use other distros, such as Fedora, Arch and so on could not build the image on their host for reasons, but one of them is the library dependencies. To provide the build system on any distros, dockerize it.
 
 
 # Architecture
-![Imgur](https://i.imgur.com/oKtkkUp.jpg)
+![Imgur](https://i.imgur.com/GmsKMGw.jpg)
 
 
 # Tutorial
@@ -26,21 +26,17 @@ $ docker run -i -t --network host --name webos -v /path/to/mountpoint:/home/webo
 ```
 ``/path/to/mountpoint`` must be a path that point to an external storage which is 100GB and above.
 
-If your distro causes an error of *SELinux* permission, add ``:Z`` flag at the end of ``-v`` like ``-v /path/to/mountpoint:/home/webos/mpoint:Z``. That is usually required on the distros related to Red Hat Linux.
+If your distro causes an error of *SELinux* permission, add ``:Z`` flag in the end of ``-v`` like ``-v /path/to/mountpoint:/home/webos/mpoint:Z``. That is usually required on the distros related to Red Hat Linux.
 
 ### 3. Get ready to build
-You could not build the image with root right away, so must be the user, **webos** that already existed.
-```
-$ su webos; cd
-```
-**webos**'s home directory is mounted to ``/path/to/mountpoint``, but it could do nothing since the mounting point has been owned by root. Instead of it, run everything with ``sudo``.
+``~/mpoint`` is a mount point that ``/path/to/mountpoint`` must be mounted, but **webos** can do nothing since the point has been owned by root. Instead of it, run everything with ``sudo``.
 
 To clone ``build-webos``,
 ```
 $ sudo git clone https://github.com/webosce/build-webos.git
 ```
 
-To let **webos** be able to read/write files, chown it.
+**webos** must be able to read/write files in the repository, chown it.
 ```
 $ sudo chown -hR webos:webos build-webos
 ```