add more rules to grammar and write more tests to cover new rules

grammar.y

@@ -14,7 +14,9 @@ class Query
           |     TERM_WITHOUT_QUOTES COLON TERM_WITH_QUOTES                      { result = {val[0] => val[2]} }
           |     expression OPERATOR_OR expression                               { result = {:OPERATOR_OR => [val[0], val[2]]} }
           |     expression OPERATOR_AND expression                              { result = {:OPERATOR_AND => [val[0], val[2]]} }
+          |     OPERATOR_NOT expression                                         { result = {:OPERATOR_NOT => val[1]} }
           |     L_BRACKET expression R_BRACKET                                  { result = val[1] }
+          |     expression expression                                           { result = {:OPERATOR_OR => [val[0], val[1]]} }
 end
 
 ---- header