compilation errors with erlang 20

I tried to compile erica with erlang 20. There are many error because of changed functions like "crypto:md5_init" or "crypto:md5_final". After replacing all obsolete functions with the new ones I get a erica binary. Unfortunately it throws
```
Uncaught error in erica: {'EXIT',
{undef,
[{couchbeam,start,[],[]},
{erica_core,run,1,
[{file,"src/erica_core.erl"},{line,41}]},
{erica,main,1,
[{file,"src/erica.erl"},{line,12}]},
{escript,run,2,
[{file,"escript.erl"},{line,759}]},
{escript,start,1,
[{file,"escript.erl"},{line,277}]},
{init,start_em,1,[]},
{init,do_boot,3,[]}]}}
```
Now I don't know what to do. Can you help? Many thanks in advance.

Reproduce the Erlang 20 build and inspect the obsolete crypto calls, then trace the startup path in src/erica_core.erl at line 41 and src/erica.erl at line 12. Investigate why couchbeam:start is unavailable; done means Erica compiles and starts successfully on Erlang 20 without the reported errors.

Written by the indexing model from the issue text.