Add Dragonwell11 for enclave build and install README.md

docs/dragonwell_install.md

@@ -0,0 +1,33 @@
+# Dragonwell11 For Enclave
+
+Dragonwell11 for enclave is an opensource project, see [here](https://github.com/alibaba/dragonwell11/tree/dragonwell-for-enclave).
+
+It's a musl-based JDK version compatible with Alpine platform and Occlum libos. Dragonwell11 for enclave will be built in a Alpine docker,
+
+you can cd the top path of dragonwell11 project, will see make.sh and musl.sh files, then './make.sh release' begin to built dragonwell11
+
+for enclave.
+
+# How to install Dragonwell11
+
+We provide three ways to install dragonwell11 jdk image:
+
+1. download dragonwell11 jdk image directly from oss, then decompress and copy it into host path /opt/occlum/toolchains/jvm
+
+   wget https://dragonwell.oss-cn-shanghai.aliyuncs.com/11/linux/x64/11.0.8.3-enclave/Dragonwell11-11.0.8.3.tar.gz
+
+2. download dragonwell11 src.rpm from oss, the src.rpm will build dragonwell11 project and then install the image automatically.
+
+   src.rpm contains dragonwell11 source code and spec file, it will build dragonwell11 and then copy the built image into
+
+   host path /opt/occlum/toolchains/jvm. Be cautious that docker should not work in root mode.
+
+   wget https://dragonwell.oss-cn-shanghai.aliyuncs.com/11/linux/x64/11.0.8.3-enclave/Dragonwell11-11.0.8.3-EnclaveExperimental.src.rpm
+   rpm -ivh dragonwell11-for-enclave-11.0.8.3-EnclaveExperimental.src.rpm --nodeps --force
+
+3. download dragonwell11 rpm from oss, the .rpm contains dragonwell11 jdk image and spec file. it will not build the dragonwell11
+
+   source code, but install the jdk image directly, which will copy the dragonwell11 image into host path /opt/occlum/toolchains/jvm.
+
+   wget https://dragonwell.oss-cn-shanghai.aliyuncs.com/11/linux/x64/11.0.8.3-enclave/Dragonwell11-11.0.8.3-EnclaveExperimental.x86_64.rpm
+   rpm -ivh dragonwell11-for-enclave-11.0.8.3-EnclaveExperimental.x86_64.rpm --nodeps --force