Minor grammatical fix for Disable Registration feature

Typos

- Very small typo fixes

fixed typo

Corrected grammar and spelling mistakes

Add postgresql support in docker deployed.

swap \n for \000, update len check, when reading receive-pack input

Add the instruction of installing gogs with PostgreSQL

Add the support of postgres as the database.
(Config the db in the build.sh file, make the DB_TYPE to 'postgres').

Replace the host with $DB_PORT, which is dependent to the database imagae's exposed port.

Replace the 'mysql' options with 'db' options, makeing the config according to the database type.