Add generatedependency command

This comment generated pip install requirement files.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/dependencies/management/commands/generaterequirements.py

@@ -0,0 +1,47 @@
+from __future__ import unicode_literals
+
+from django.core import management
+from django.utils.translation import ugettext_lazy as _
+
+from ...classes import PythonDependency, DependencyGroup
+
+
+class Command(management.BaseCommand):
+    help = 'Generate Python requirement files.'
+
+    def add_arguments(self, parser):
+        parser.add_argument('environment', nargs='?', help='Environment name')
+        parser.add_argument(
+            '--exclude', action='store', dest='exclude', help=_(
+                'Comma separated names of dependencies to exclude from the '
+                'list generated.'
+            ),
+        )
+        parser.add_argument(
+            '--only', action='store', dest='only', help=_(
+                'Comma separated names of dependencies to show in the list '
+                'while excluding every other one.'
+            ),
+        )
+
+    def handle(self, *args, **options):
+        dependency_list = PythonDependency.get_for_attribute(
+            attribute_name='environment__name',
+            attribute_value=options['environment'], subclass_only=True
+        )
+        exclude_list = (options['exclude'] or '').split(',')
+        only_list = (options['only'] or '').split(',')
+        result = []
+
+        for dependency in dependency_list:
+            if only_list != ['']:
+                if dependency.name in only_list:
+                    result.append(dependency)
+            else:
+                result.append(dependency)
+
+        for dependency in result:
+            if dependency.name not in exclude_list:
+                print(
+                    '{}{}'.format(dependency.name, dependency.version_string)
+                )