Reformat and add db backup note

CHANGELOG.md

@@ -1,29 +1,31 @@
 # CHANGELOG
 
-**0.15.0 (2022-xx-xx):**
+## 0.15.0 (2022-xx-xx)
 
-**BREAKING**:
+**Note:** Take a backup of your database before upgrading.
+
+### BREAKING
 
 - Boundaries between Namespaces has been removed and all nodes can communicate by default [#357](https://github.com/juanfont/headscale/pull/357)
   - To limit access between nodes, use [ACLs](./docs/acls.md).
 
-**Changes**:
+### Changes
 
 - Fix a bug were the same IP could be assigned to multiple hosts if joined in quick succession [#346](https://github.com/juanfont/headscale/pull/346)
 - Simplify the code behind registration of machines [#366](https://github.com/juanfont/headscale/pull/366)
   - Nodes are now only written to database if they are registrated successfully
 
-**0.14.0 (2022-02-24):**
+## 0.14.0 (2022-02-24)
 
-**UPCOMING BREAKING**:
-From the **next** version (`0.15.0`), all machines will be able to communicate regardless of
+**UPCOMING ### BREAKING
+From the **next\*\* version (`0.15.0`), all machines will be able to communicate regardless of
 if they are in the same namespace. This means that the behaviour currently limited to ACLs
 will become default. From version `0.15.0`, all limitation of communications must be done
 with ACLs.
 
 This is a part of aligning `headscale`'s behaviour with Tailscale's upstream behaviour.
 
-**BREAKING**:
+### BREAKING
 
 - ACLs have been rewritten to align with the bevaviour Tailscale Control Panel provides. **NOTE:** This is only active if you use ACLs
   - Namespaces are now treated as Users
@@ -31,17 +33,17 @@ This is a part of aligning `headscale`'s behaviour with Tailscale's upstream beh
   - Tags should now work correctly and adding a host to Headscale should now reload the rules.
   - The documentation have a [fictional example](docs/acls.md) that should cover some use cases of the ACLs features
 
-**Features**:
+### Features
 
 - Add support for configurable mTLS [docs](docs/tls.md#configuring-mutual-tls-authentication-mtls) [#297](https://github.com/juanfont/headscale/pull/297)
 
-**Changes**:
+### Changes
 
 - Remove dependency on CGO (switch from CGO SQLite to pure Go) [#346](https://github.com/juanfont/headscale/pull/346)
 
 **0.13.0 (2022-02-18):**
 
-**Features**:
+### Features
 
 - Add IPv6 support to the prefix assigned to namespaces
 - Add API Key support
@@ -52,7 +54,7 @@ This is a part of aligning `headscale`'s behaviour with Tailscale's upstream beh
   - `oidc.domain_map` option has been removed
   - `strip_email_domain` option has been added (see [config-example.yaml](./config_example.yaml))
 
-**Changes**:
+### Changes
 
 - `ip_prefix` is now superseded by `ip_prefixes` in the configuration [#208](https://github.com/juanfont/headscale/pull/208)
 - Upgrade `tailscale` (1.20.4) and other dependencies to latest [#314](https://github.com/juanfont/headscale/pull/314)
@@ -61,35 +63,35 @@ This is a part of aligning `headscale`'s behaviour with Tailscale's upstream beh
 
 **0.12.4 (2022-01-29):**
 
-**Changes**:
+### Changes
 
 - Make gRPC Unix Socket permissions configurable [#292](https://github.com/juanfont/headscale/pull/292)
 - Trim whitespace before reading Private Key from file [#289](https://github.com/juanfont/headscale/pull/289)
 - Add new command to generate a private key for `headscale` [#290](https://github.com/juanfont/headscale/pull/290)
 - Fixed issue where hosts deleted from control server may be written back to the database, as long as they are connected to the control server [#278](https://github.com/juanfont/headscale/pull/278)
 
-**0.12.3 (2022-01-13):**
+## 0.12.3 (2022-01-13)
 
-**Changes**:
+### Changes
 
 - Added Alpine container [#270](https://github.com/juanfont/headscale/pull/270)
 - Minor updates in dependencies [#271](https://github.com/juanfont/headscale/pull/271)
 
-**0.12.2 (2022-01-11):**
+## 0.12.2 (2022-01-11)
 
 Happy New Year!
 
-**Changes**:
+### Changes
 
 - Fix Docker release [#258](https://github.com/juanfont/headscale/pull/258)
 - Rewrite main docs [#262](https://github.com/juanfont/headscale/pull/262)
 - Improve Docker docs [#263](https://github.com/juanfont/headscale/pull/263)
 
-**0.12.1 (2021-12-24):**
+## 0.12.1 (2021-12-24)
 
 (We are skipping 0.12.0 to correct a mishap done weeks ago with the version tagging)
 
-**BREAKING**:
+### BREAKING
 
 - Upgrade to Tailscale 1.18 [#229](https://github.com/juanfont/headscale/pull/229)
   - This change requires a new format for private key, private keys are now generated automatically:
@@ -97,19 +99,19 @@ Happy New Year!
     2. Restart `headscale`, a new key will be generated.
     3. Restart all Tailscale clients to fetch the new key
 
-**Changes**:
+### Changes
 
 - Unify configuration example [#197](https://github.com/juanfont/headscale/pull/197)
 - Add stricter linting and formatting [#223](https://github.com/juanfont/headscale/pull/223)
 
-**Features**:
+### Features
 
 - Add gRPC and HTTP API (HTTP API is currently disabled) [#204](https://github.com/juanfont/headscale/pull/204)
 - Use gRPC between the CLI and the server [#206](https://github.com/juanfont/headscale/pull/206), [#212](https://github.com/juanfont/headscale/pull/212)
 - Beta OpenID Connect support [#126](https://github.com/juanfont/headscale/pull/126), [#227](https://github.com/juanfont/headscale/pull/227)
 
-**0.11.0 (2021-10-25):**
+## 0.11.0 (2021-10-25)
 
-**BREAKING**:
+### BREAKING
 
 - Make headscale fetch DERP map from URL and file [#196](https://github.com/juanfont/headscale/pull/196)