Change Enum name generation in PgSQL and quote it

[SOHELAHMED7]

2 changes related to enum in PgSQL is required

1. enum type name generation should include table name. Currently it conflict with other column name. enum_column_name to enum_table_name_column_name. This is required in case like Task.status can be one of ["open", "working", "closed"] and Invoice.status can be one of draft, ready or billed (bug)
2. quote enum type name to preserve case sensitive column name; see Quote issue to preserve the case of the column name #127 but for enum type name

[SOHELAHMED7]

Also add tests for #127