Update docs badge in README

Update the URL of the docs badge to include it from inch-ci.org instead of inch-pages.github.io (the former being the successor of the Inch Pages project).

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Merge pull request #126 from rrrene/patch-2

Update docs badge in README
Allow passing non-Proc callables as guards
Merge pull request #130 from GoodGuide/allow-non-proc-callable-guards

Allow passing non-Proc callables as guards
Bump version to 0.1.13.
Make reading state work for non-AR models (by Randy Schmidt [@r38y]).
add can_execute_event? to check against guard clauses
use brackets for method args
remove unnecessary assertion
use existing can_? definition