update varchar to 255 for the unique value to work for the migrations table.

store/datastore/ddl/migrate.go

@@ -99,7 +99,7 @@ INSERT IGNORE INTO migrations (name) VALUES
 
 var createMigrationsTable = `
 CREATE TABLE IF NOT EXISTS migrations (
- name VARCHAR(512)
+ name VARCHAR(255)
 ,UNIQUE(name)
 )
 `

store/datastore/ddl/mysql/ddl_gen.go

@@ -150,7 +150,7 @@ func selectCompleted(db *sql.DB) (map[string]struct{}, error) {
 
 var migrationTableCreate = `
 CREATE TABLE IF NOT EXISTS migrations (
- name VARCHAR(512)
+ name VARCHAR(255)
 ,UNIQUE(name)
 )
 `