Run load/stress tests across different databases

[cabol]

Pick a few databases with standard hardware and try out nebulex_ecto, run some load tests using for instance basho_bench. The idea is to pick at least two DB options, e.g.: PostgreSQL and MySQL, and run load tests using nebulex_ecto.

NOTE: This is the continuation of the Nebulex Load/Stress Tests Issue – some load tests were run already there

[fire]

I recommend we use travis to run the tests. Travis is a known quantity and as long as the tests are run on the same setup, the results should be comparable.

Any suggestions?