Add documentation

[os-moussao]

Issue Type

Docs

Description

• Add README.md
• Add JSDoc comments
• Generate documentation (may use typedoc for that)

Example

  /**
   * Add columns to the SELECT clause of the SQL query.
   * @param selection A column name, a record of columns-aliases, or an array containing a mix both.
   * @param fromTable Optional. If specified, all selected columns are prefixed with 'fromTable.'.
   * @returns The current instance of the QueryBuilder for method chaining.
   */
  select(...)