Encodes a condition into Filtrex.Fragment as an expression with values. Implementing this protocol is required for any new conditions. See Filtrex.Utils.Encoder for helper methods with this implementation.

Example:

defimpl Filtrex.Encoder, for: Filtrex.Condition.Text do
  def encode(%Filtrex.Condition.Text{column: column, comparator: "equals", value: value}) do
    %Filtrex.Fragment{expression: "#{column} = ?", values: [value]}
  end
end