docs: add CONTRIBUTING + open-source FAQ (#178)

* add CONTRIBUTING.md + mention conduct from there not in README

* docs: add FAQ

CONTRIBUTING.md

@@ -0,0 +1,14 @@
+# Contributing
+
+## What contributions are accepted?
+
+In short, we are open to nearly all contributions! We love feedback in all forms, issues, comments, PRs, etc!
+
+Unless you feel confident your change will be accepted (trivial bug fixes, code cleanup, etc) you should first create an issue to discuss your change with us. In this way, we can help ensure that your time will be well spent and your contribution will be accepted.
+
+> Exception: If you contribute functionality that already exists as a [paid Sourcegraph feature](https://about.sourcegraph.com/pricing/), we are unlikely to accept it. Consult us beforehand for a definitive answer. (We'll add more details about the process here, and they'll be similar to [GitLab's stewardship principles](https://about.gitlab.com/stewardship/#contributing-an-existing-ee-feature-to-ce).)
+
+## Code of Conduct
+
+All interactions with the Sourcegraph open source project are governed by the
+[Sourcegraph Code of Conduct](./docs/conduct.md).

README.md

@@ -52,12 +52,9 @@ For detailed instructions and troubleshooting, see the [local development docume
 
 The `docs` folder has additional documentation for developing and understanding Sourcegraph:
 
+- [Project FAQ](./docs/FAQ.md)
 - [Architecture](./docs/architecture.md): high-level architecture
 - [Database setup](./docs/storage.md): database setup and best practices
 - [Style guide](./docs/style.md)
 - [GraphQL API](./docs/api.md): useful tips when modifying the GraphQL API
-
-## Code of Conduct
-
-All interactions with the Sourcegraph open source project are governed by the
-[Sourcegraph Code of Conduct](./docs/conduct.md).
+- [Contributing](./CONTRIBUTING.md)

docs/FAQ.md

@@ -0,0 +1,19 @@
+# Sourcegraph Project FAQ
+
+> Note: This document primarily talks about the Sourcegraph open source project itself, not e.g. features of Sourcegraph.
+
+## What kinds of contributions are accepted?
+
+See [CONTRIBUTING.md](../CONTRIBUTING.md).
+
+## What license is Sourcegraph under?
+
+Sourcegraph is under the [Apache License v2.0](../LICENSE).
+
+## Is all of Sourcegraph open source?
+
+This repository is 100% open source and builds a product known as Sourcegraph OSS. Sourcegraph OSS omits certain trademarks, logos, and [paid enterprise features](https://about.sourcegraph.com/pricing/) from the official Sourcegraph build to make it open-source.
+
+The official, free Sourcegraph build is called Sourcegraph Core and includes these additions, so it's not open source. The reason why we include these features in the official build is to provide a smooth upgrade path to Sourcegraph Enterprise (you can just supply a license key to activate the features, with no migration necessary).
+
+> Note: To build a 100% open-source `sourcegraph/server` image, use `dev/dev-sourcegraph-server.sh`.