Change sqlalchemy version

[FayasNoushad]

For avoiding sqlalchemy.exc.NoSuchModuleError: Can't load plugin: sqlalchemy.dialects:postgres

[jk6521]

To avoid that you should use postgresql:// instead of postgres://

[FayasNoushad]

Ok

[FayasNoushad]

Ok

[PaulSonOfLars]

The purpose of this PR is very unclear.

Why does pinning the version fix this? What changed in newer sqlalchemy versions? What is the actual issue?

[jk6521]

The purpose of this PR is very unclear.

Why does pinning the version fix this? What changed in newer sqlalchemy versions? What is the actual issue?

In older version of sqlalchemy it accepted both postgres:// and postgresql:// but in the newer version they stopped support for postgres:// in database URI. The error he mentioned is happening mostly on heroku since the DATABASE_URL from heroku-postgres can't be edited and they haven't added support for this.