Problem:
1. We don't have a changelog, but it's a good practice to have one.
2. Package version is currently 0.1.0.0. However, I've already
uploaded some old version of code with this package version because
I needed it for TM-77. So I think we should use 0.2.0.0 for the
initial release. Also proper morley-prelude was uploaded with version
0.1.0.3.
Solution:
1. Add a changelong.
2. Set morley version to 0.2.0 and morley-prelude version to 0.1.0.3.