docs: add upgrading instructions

[ilgooz]

No description provided.

[barriebyron]

@ilgooz it seems like we can provide some comfort here to existing users with running apps.
Do we want to provide more upgrade guidance?
Users will want to know what happens to their current apps and if they need to make changes? do they need to stop and restart their server? change any settings?

[barriebyron]

Suggested change

	## Upgrading
	Remove any previous Starport installation. To do so, run `rm $(which starport)` command with or without `sudo` depending on your user and repeat until there is no `starport` binary left in your system.
	Then follow the regular installation instructions.
	## Upgrading Your Starport Installation
	Before you install a new version of Starport, remove all existing Starport installations.
	To remove the current Starport installation:
	1. Run the `which starport` command to locate the Starport executable file. By default, the Starport binary is installed in `/usr/local/bin`.
	1. Change to the directory where Starport is installed. For example:
	```bash
	cd /usr/local/bin
	```
	1. Run the remove command. Depending on your user permissions, run the command with or without `sudo`:
	```bash
	rm starport
	```
	1. Repeat these steps until all `starport` installations are removed from your system.
	After all existing Starport installations are removed, follow the [Installing Starport with cURL](#installing-starport-with-curl) instructions. For details on version features and changes, see the [changelog.md](https://github.com/tendermint/starport/blob/develop/changelog.md) in the repo.

[barriebyron]

@ilgooz oooh after I uninstalled Starport from the default location, I was surprised to find an unexpected Starport installation:

which starport
/Users/barriebyron/go/bin/starport

[barriebyron]

@ilgooz I think ^^ unexpected installation happened before I knew better than to install go using brew. I had issues with the PATH variables.
Since then, I developed: https://github.com/cosmos/sdk-tutorials/blob/master/TECHNICAL-SETUP.md for onboarding awesomeness.

[ilgooz]

Yep, that usually happens. Different kind of installation options (curl, homebrew, git clone & make install) adds the Starport binary to a different bin folder and users usually forget about them.

Even if you remove a single installation and install a new one, you may end up using another old version of Starport that is still not removed from your system. It is all about the order of presence of the bin dirs in $PATH. This is why I think we should recommend users to uninstall any previous installations.

[fadeev]

I was surprised to find an unexpected Starport installation:

starport is installed in ~/go/bin when you build it from source, so that's expected.

[ilgooz]

Two things I would fix from your change requests:

• /usr/local/bin is not the default bin dir for everyone. It depends on the system. Maybe we should rm this.
• We don't need two step process for removing the binary by first cd'ing to dir. We can just recommend rm $(which starport) or run which starport first and if any path (binary) found rm xxx it.

[ilgooz]

@barriebyron I think we can recommend them to stop chains (stopping serve) before the upgrade.

Migration instructions like changing any configs I think could be described in another page, not necessarily here to keep things simple in the installation docs.

Maybe we can create a migration.md for this purpose later in another PR. In this page we could just show how to migrate things from an older version to the next one when needed.

[ilgooz]

Hey @barriebyron please feel free to add your change requests directly to the PR.

[fadeev]

@barriebyron great suggested changes!

[fadeev]

Looks great!

[barriebyron]

Ilker, I don't know what the rm $which starport command is, but I trust you. Make sure I got it right.