Exclude not critical test (#2)

* Exclude not critical test

* Add exclude-tests option

* Update documentation

* Clean forgotten print

* Improve Readme, with examples

django_migration_linter/sql_analyser.py

@@ -70,11 +70,11 @@ migration_tests = (
 )
 
 
-def analyse_sql_statements(sql_statements):
+def analyse_sql_statements(sql_statements, exclude_tests):
     errors = []
     for statement in sql_statements:
         for test in migration_tests:
-            if test["fn"](statement, errors=errors):
+            if test["code"] not in exclude_tests and test["fn"](statement, errors=errors):
                 logger.debug("Testing {0} -- ERROR".format(statement))
                 table_search = re.search("TABLE `([^`]*)`", statement, re.IGNORECASE)
                 col_search = re.search("COLUMN `([^`]*)`", statement, re.IGNORECASE)