Allow customizing SSL CA certificate

by adding a `ssl_ca_cert` configuration option

modules/swagger-codegen/src/main/resources/ruby/swagger/configuration.mustache

@@ -7,6 +7,14 @@ module {{moduleName}}
                     :scheme, :host, :base_path, :user_agent, :debug, :logger, :inject_format,
                     :force_ending_format, :camelize_params, :user_agent, :verify_ssl
 
+      # Set this to customize the certificate file to verify the peer.
+      #
+      # @return [String] the path to the certificate file
+      #
+      # @see The `cainfo` option of Typhoeus, `--cert` option of libcurl. Related source code:
+      #   https://github.com/typhoeus/typhoeus/blob/master/lib/typhoeus/easy_factory.rb#L145
+      attr_accessor :ssl_ca_cert
+
       # Defaults go in here..
       def initialize
         @format = 'json'

modules/swagger-codegen/src/main/resources/ruby/swagger/request.mustache

@@ -166,6 +166,7 @@ module {{moduleName}}
       def make
         request_options = {
           :ssl_verifypeer => Swagger.configuration.verify_ssl,
+          :cainfo => Swagger.configuration.ssl_ca_cert,
           :headers => self.headers.stringify_keys,
           :verbose => Swagger.configuration.debug
         }

samples/client/petstore/ruby/lib/swagger_client/swagger/configuration.rb

@@ -7,6 +7,14 @@ module SwaggerClient
                     :scheme, :host, :base_path, :user_agent, :debug, :logger, :inject_format,
                     :force_ending_format, :camelize_params, :user_agent, :verify_ssl
 
+      # Set this to customize the certificate file to verify the peer.
+      #
+      # @return [String] the path to the certificate file
+      #
+      # @see The `cainfo` option of Typhoeus, `--cert` option of libcurl. Related source code:
+      #   https://github.com/typhoeus/typhoeus/blob/master/lib/typhoeus/easy_factory.rb#L145
+      attr_accessor :ssl_ca_cert
+
       # Defaults go in here..
       def initialize
         @format = 'json'

samples/client/petstore/ruby/lib/swagger_client/swagger/request.rb

@@ -165,6 +165,7 @@ module SwaggerClient
       def make
         request_options = {
           :ssl_verifypeer => Swagger.configuration.verify_ssl,
+          :cainfo => Swagger.configuration.ssl_ca_cert,
           :headers => self.headers.stringify_keys,
           :verbose => Swagger.configuration.debug
         }