series_import_requests: increase url length.

If url consists only from non-ascii symbols, we effectively will be able to save a URL up to 255
characters.

Fix #772

Author: php-coder

src/main/resources/liquibase/version/0.4.xml

@@ -43,5 +43,6 @@
 	<include file="0.4/2017-12-18--unique_series_id_in_import_requests.xml" relativeToChangelogFile="true" />
 	<include file="0.4/2017-12-21--solovyov_catalog.xml" relativeToChangelogFile="true" />
 	<include file="0.4/2017-12-21--zagorski_catalog.xml" relativeToChangelogFile="true" />
+	<include file="0.4/2017-12-30--series_import_requests_url_length2.xml" relativeToChangelogFile="true" />
 
 </databaseChangeLog>

src/main/resources/liquibase/version/0.4/2017-12-30--series_import_requests_url_length2.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<databaseChangeLog
+		xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
+		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
+		http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.0.xsd">
+	
+	<changeSet id="modify-series_import_requests-url-field" author="php-coder" context="scheme">
+		<!--
+			767 bytes is the maximum length for the index key prefix in MySQL 5.6 and prior versions.
+			This limit was increased up to 3072 bytes in 5.7 version because innodb_large_prefix option
+			was enabled by default and innodb_file_format was changed to use Barracuda by default.
+			
+			In other words, we can specify a value greater than 767 in production environment but
+			I decided to use this value for now because we have a different MySQL 5.6.33 on TravisCI
+			where migration fails to apply. I hope that this value will fulfill our requirements,
+			because it's enough to hold about 255 non-ascii characters.
+		-->
+		<modifyDataType tableName="series_import_requests" columnName="url" newDataType="VARCHAR(767)" />
+	</changeSet>
+	
+</databaseChangeLog>