Bayesian meta-analysis in brms

[edited Feb 27, 2019] Preamble I released the first bookdown version of my Statistical Rethinking with brms, ggplot2, and the tidyverse project a couple weeks ago. I consider it the 0.9.0 version. I wanted a little time to step back from the project before giving it a final edit for the first major edition. I also wanted to give others a little time to take a look and suggest edits, which some thankfully have.