Easiest Way to Migrate data from MySQL to MongoDB
Migrating between a RDBMS and a NoSQL DB is not the easiest thing.
If you can dump your data to JSON (or XML), I know that Navicat for MongoDB can import data in either of those formats.  

I know that MySQL workbench can export in JSON format.  You might also want to try a Navicat for MySQL.  I use it and I know that it can export to either of those formats.

Navicat products aren't free, but both come with a 14 day trial.  That should be plenty long enough to get the job done.

Let me know how that works for you!

Dave