Add sqlite build tag

This adds a sqlite build tag so that you don't have to have the sqlite
import commented out in code and users can run:
    go build -tags sqlite
if they want to have sqlite support enabled.  It is disabled by default
so nothing changes with the default go get or build commands.

combine getCommit ById and ByBranch in routers/repo/commit.go

Add Docker Deploy Support

Update the guide of how to deploy gogs in docker with the scripts.

Git