Merge branch 'zhangxin/feature/162' of https://github.com/ascrutae/sky-walking into zhangxin/feature/162

fix the image name of collector issue and push docker images when skywalking is tagged and the branch is master

Merge branch 'zhangxin/feature/162' of https://github.com/ascrutae/sky-walking into zhangxin/feature/162

fix the image name of collector issue and push docker images when skywalking is tagged and the branch is master

fix the image name of collector issue and push docker images when skywalking is tagged and the branch is master

Merge branch 'zhangxin/feature/162' of https://github.com/ascrutae/sky-walking into zhangxin/feature/162

Update README.md

Support plugin for MongoDB

Response for "Add checkstyle", close #149 

fix collector cannot start issue

Add “checkStyle.xml” and “codeStyle.xml” files, varify the code-style when “mvn compile” and CI. This is the initialized commit.

fix start error issue