Ruby: add downgrade scripts

ruby/downgrades/24d81950f3ab7e67e14553e1a5111a04e8ae8445/block_argument_def.ql

@@ -0,0 +1,13 @@
+class AstNode extends @ruby_ast_node {
+  string toString() { none() }
+}
+
+class Location extends @location {
+  string toString() { none() }
+}
+
+from AstNode ruby_block_argument, AstNode child, Location location
+where
+  ruby_block_argument_def(ruby_block_argument, location) and
+  ruby_block_argument_child(ruby_block_argument, child)
+select ruby_block_argument, child, location

ruby/downgrades/24d81950f3ab7e67e14553e1a5111a04e8ae8445/block_parameter_def.ql

@@ -0,0 +1,13 @@
+class AstNode extends @ruby_ast_node {
+  string toString() { none() }
+}
+
+class Location extends @location {
+  string toString() { none() }
+}
+
+from AstNode ruby_block_parameter, AstNode name, Location location
+where
+  ruby_block_parameter_def(ruby_block_parameter, location) and
+  ruby_block_parameter_name(ruby_block_parameter, name)
+select ruby_block_parameter, name, location

ruby/downgrades/24d81950f3ab7e67e14553e1a5111a04e8ae8445/ruby_pair_def.ql

@@ -0,0 +1,13 @@
+class AstNode extends @ruby_ast_node {
+  string toString() { none() }
+}
+
+class Location extends @location {
+  string toString() { none() }
+}
+
+from AstNode ruby_pair, AstNode key, AstNode value, Location location
+where
+  ruby_pair_def(ruby_pair, key, location) and
+  ruby_pair_value(ruby_pair, value)
+select ruby_pair, key, value, location

ruby/downgrades/24d81950f3ab7e67e14553e1a5111a04e8ae8445/upgrade.properties

@@ -0,0 +1,9 @@
+description: Update grammar
+compatibility: backwards
+ruby_expression_reference_pattern_def.rel: delete
+ruby_block_argument_child.rel: delete
+ruby_block_parameter_name.rel: delete
+ruby_pair_value.rel: delete
+ruby_block_argument_def.rel: run block_argument_def.qlo
+ruby_block_parameter_def.rel: run block_parameter_def.qlo
+ruby_pair_def.rel: run ruby_pair_def.qlo