lemmy/docs/src/contributing_local_development.md

Requirements

• Rust
• Yarn
• Postgres

Set up Postgres DB

 psql -c "create user lemmy with password 'password' superuser;" -U postgres
 psql -c 'create database lemmy with owner lemmy;' -U postgres
 export LEMMY_DATABASE_URL=postgres://lemmy:password@localhost:5432/lemmy

Running

git clone https://github.com/dessalines/lemmy
cd lemmy
./install.sh
# For live coding, where both the front and back end, automagically reload on any save, do:
# cd ui && yarn start
# cd server && cargo watch -x run